cyclin-d1 and Parathyroid-Neoplasms

Paragangliomas are relatively uncommon neoplasms that arise in adrenal and extra-adrenal paraganglia of the autonomic nervous system. Parasympathetic paraganglioma develop predominantly in the head and neck. It is exceedingly uncommon to develop a primary intraparathyroid paraganglioma. There is only a single case report in the English literature. The information from the single previous case report (Medline 1960-2009) was combined with this case report. Our patient was a 69 year old woman who presented with a thyroid gland mass, with extension into the substernal space. The patient had a history of renal cell carcinoma removed 18 months before. At surgery, a thyroid lobectomy and a parathyroidectomy were performed. The parathyroid tissue showed a very well defined zellballen arrangement of paraganglion cells within the parenchyma of the parathyroid gland. The cells had ample basophilic, granular cytoplasm. The nuclei were generally round to oval with 'salt-and-pepper' nuclear chromatin distribution. There was a richly vascularized stroma. Mitotic figures, necrosis, invasive growth, and profound nuclear pleomorphism were absent. The neoplastic cells were strongly and diffusely immunoreactive with chromogranin, synaptophysin, CD56, and focally with cyclin-D1. The paraganglioma showed a delicate S-100 protein positive supporting sustentacular framework. Keratin, CD10, PTH, calcitonin and RCC markers were negative. The patient showed no stigmata of Multiple Endocrine Neoplasia (MEN) and has no paraganglioma in any other anatomic site. She is alive without any additional findings 12 months after surgery. Isolated paraganglioma within the parathyroid is rare, and should be separated from parathyroid adenoma, hyperplasia or metastatic disease to assure appropriate management.

Topics: Aged; Biomarkers, Tumor; CD56 Antigen; Cell Nucleus; Chromogranins; Cyclin D1; Disease-Free Survival; Female; Humans; Paraganglioma, Extra-Adrenal; Parathyroid Neoplasms; Synaptophysin; Thyroidectomy

Topics: Adenocarcinoma; Chromosomes, Human, Pair 11; Cyclin D1; Diagnosis, Differential; Gene Rearrangement; Humans; Hypercalcemia; Hyperparathyroidism, Primary; Parathyroid Hormone; Parathyroid Neoplasms; Parathyroidectomy; Prognosis

Parathyroid carcinoma is an uncommon malignancy. It accounts for less than 1% of cases of primary hyperparathyroidism (HPT). It is manifested by severe hypercalcemia and up to 50% of patients will have concomitant kidney or bone disease. The etiology of parathyroid carcinoma is unknown, however, the recently discovered HRPT2 gene, a tumor suppressor gene encoding for the protein parafibromin, has been implicated in the pathogenesis. Identification of inactivating germ-line mutations in HRPT2 has significant implications for diagnosis and management. This article summarizes the genetic aspects of parathyroid carcinoma, reviews its clinical manifestations, and outlines the principles of surgical therapy, the indications for adjuvant therapy, and the use of bisphosphonate and calcimimetic agents for management of hypercalcemia.

Topics: Carcinoma; Cyclin D1; Genes, Retinoblastoma; Genes, Tumor Suppressor; Germ-Line Mutation; Humans; Hypercalcemia; Hyperparathyroidism; Parathyroid Hormone; Parathyroid Neoplasms; Proteins; Proto-Oncogene Proteins; Tumor Suppressor Proteins

Human neuroendocrine tumors exhibit unique biological properties, and defining the molecular genetic alterations that underlie these distinctive features remains an important challenge. In addition to the MEN1 tumor suppressor gene, the cyclin D1 oncogene has demonstrated a role in the pathogenesis of parathyroid and gastroenteropancreatic neuroendocrine tumors. Up-regulation of cyclin D1 is observed early in tumor formation, implying a possible role in tumor initiation. Overexpression of cyclin D1 in the parathyroid glands of mice resulted in the tandem regulation of cellular proliferation and hormonal secretion, a feature intrinsic to neuroendocrine tumors.

Topics: Cyclin D1; Gastrointestinal Neoplasms; Humans; Neuroendocrine Tumors; Pancreatic Neoplasms; Parathyroid Neoplasms

Primary hyperparathyroidism (pHPT) is a common endocrine disorder that predominantly affects postmenopausal women. It is mostly caused by solitary tumours within the parathyroid glands. Although the pathophysiology of pHPT is still incompletely understood, recent studies provide new clues on the development and cellular growth of tumours within the parathyroids associated with hypersecretion of parathyroid hormone and hypercalcaemia. The natural course of pHPT is rather benign. Nowadays, it has become an oligo- or asymptomatic disease often only detected by routine blood tests. These facts raise the question whether to perform parathyroidectomy on oligo- and asymptomatic patients with pHPT or whether it is possible to monitor these patients without surgery. The aim of this article is to review the literature as regards (i) the pathophysiological mechanisms that underlie parathyroid neoplasia and (ii) the defective calcium-sensing in patients with pHPT (iii) environmental and/or genetic risk factors that predispose to or promote parathyroid neoplasia, as well as (iv) alternative approaches to treat oligo- and asymptomatic patients with pHPT medically.

Topics: Adenoma; Aged; Calcium; Chromosome Aberrations; Cyclin D1; Diphosphonates; Estrogens; Female; Gene Rearrangement; Genetic Predisposition to Disease; Humans; Hyperparathyroidism; Male; Middle Aged; Parathyroid Neoplasms; Proto-Oncogene Proteins; Risk Factors; Selective Estrogen Receptor Modulators

Topics: Adenoma; Animals; Calcium; Cloning, Molecular; Cyclin D1; Humans; Mammary Neoplasms, Animal; Oncogenes; Parathyroid Hormone; Parathyroid Neoplasms

This article will primarily focus on the molecular pathogenesis of common, sporadic (nonfamilial) parathyroid adenomas; two genes currently have established roles in the development of these tumors. The cyclin D1/PRAD1 gene was identified as a clonally activated oncogene in parathyroid adenomas and has subsequently been established as a major contributor to human neoplasia. Overexpression of cyclin D1, a key regulator of the cell cycle, has been implicated in the pathogenesis of 20-40% of sporadic parathyroid adenomas. That such cyclin D1 overexpression indeed constitutes a stimulus to excessive parathyroid cell proliferation has been confirmed experimentally by the development of a transgenic mouse model with parathyroid-targeted overexpression of cyclin D1. Parathyroid hormone (PTH)-cyclin D1 transgenic mice develop parathyroid hypercellularity, biochemical hyperparathyroidism, and a shifted in vivo parathyroid-calcium setpoint; these mice constitute an animal model of human hyperparathyroidism in which aspects of tumorigenesis, parathyroid secretory setpoint control, and the pathophysiology of the chronic hyperparathyroid state can be further investigated. The MEN1 tumor suppressor is the only other gene to date with an established role in the pathogenesis of sporadic parathyroid adenomatosis. Specific clonal alterations involving somatic mutation and/or deletion of both MEN1 alleles have been demonstrated in about 15-20% of sporadic parathyroid adenomas. Allelic losses on 11q occur in roughly twice this number of adenomas, raising the still-unresolved possibility that an additional tumor suppressor gene on 11q may be the functional target of many of these acquired deletions. A mouse model of MEN1 deficiency causes a phenotype that includes parathyroid hypercellularity albeit unaccompanied by biochemical hyperparathyroidism, and additional mouse models in which menin deficiency is targeted to the parathyroids will likely provide additional important insights. The MEN1 gene product menin may have a role in transcriptional regulation involving JunD; several other menin-interacting proteins have also been identified. The in vivo mechanism of menin's actions, with special attention to its role as a parathyroid oncosuppressor, will be important to establish, as will the potential interrelationships between these pathways and those involving cyclin D1. A number of genes, put forth as candidate tumor suppressors based on their genomic locations, roles in fami

Topics: Adenoma; Cyclin D1; Drosophila Proteins; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; Hyperparathyroidism; Mutation; Neoplasm Proteins; Parathyroid Neoplasms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-ret; Receptor Protein-Tyrosine Kinases; Receptors, Calcitriol; Receptors, Calcium-Sensing; Receptors, Cell Surface

Primary hyperparathyroidism (pHPT), generally caused by a monoclonal parathyroid adenoma, is a common endocrinopathy. Until recently, the genesis of the disease was poorly understood but during the past decade the molecular pathology of parathyroid tumor development has begun to be unveiled. This review summarizes recent advances in our understanding of genetic predisposition to pHPT, and the role of vitamin D receptor gene (VDR) variants in development of the disease. It has been shown that the multiple endocrine neoplasia tumor suppressor gene (MEN1) is mutated in parathyroid adenomas, and overexpression of the cyclin D1 oncogene [PRAD1 (parathyroid adenoma 1)] seems to contribute to parathyroid tumorigenesis. Several familial hyperparathyroid disorders have been studied, and the identification and characterization of the disease-causing genes have contributed to our understanding of parathyroid physiology and pathophysiology.

Topics: Adenoma; Cyclin D1; Genetic Predisposition to Disease; Humans; Hyperplasia; Multiple Endocrine Neoplasia Type 1; Mutation; Parathyroid Glands; Parathyroid Neoplasms; Receptors, Calcitriol

Primary hyperparathyroidism (HPT), most commonly due to parathyroid adenoma, is a disorder characterized by excessive secretion of PTH. So far, abnormalities in two genes, cyclin D1 and MEN1, have been implicated in the development of parathyroid adenomas. Cyclin D1, now an established Oncogene involved in numerous human cancers, was first identified and recognized as an Oncogene in the study of parathyroid tumors. A subset of parathyroid adenomas contains a clonal rearrangement that places the PTH gene's regulatory sequences in proximity to the cyclin D1 Oncogene causing its overexpression, and 20-40% of parathyroid adenomas overexpress the cyclin D1 protein. Transgenic animal models have further confirmed the role of cyclin D1 as a driver of abnormal parathyroid cell proliferation. Future studies on the mechanism of cyclin D1's oncogenicity and its interactions with other parathyroid growth regulators will further our understanding of parathyroid cell biology and may prove useful clinically.

Topics: Cell Transformation, Neoplastic; Cloning, Molecular; Cyclin D1; Forecasting; Humans; Hyperparathyroidism; Parathyroid Neoplasms

Topics: Adenoma; Animals; Chromosomes, Human, Pair 11; Cyclin D1; Cyclins; Gene Amplification; Gene Expression Regulation; Humans; Lymphoma, B-Cell; Neoplasms; Oncogene Proteins; Parathyroid Neoplasms

Two molecular defects have been described in parathyroid adenomas: rearrangement and overexpression of the PRAD1/cyclin D1 oncogene and allelic loss of chromosome 11 DNA, often including the multiple endocrine neoplasia type 1 (MEN1) putative tumor suppressor gene region. In an effort to identify additional parathyroid tumor suppressor genes, we examined 25 parathyroid adenomas for tumor-specific allelic loss of polymorphic DNA loci located near known or candidate tumor suppressor genes. Control leukocyte DNA from all 25 patients was heterozygous for 1 or more of the 9 chromosome 1 markers examined. Allelic loss at 1 or more of these informative loci on chromosome 1 was observed in 10 of 25 (40%) adenomas. Although many tumors lost extensive regions on chromosome 1, all but one of these tumors had allelic loss of distal 1p (1p32-pter); four tumors also lost loci on 1q. Allelic loss at 11q13, the site of the MEN1 gene, was detected in 5 of 21 (24%) informative cases, including 3 with 1p loss. In contrast, allelic loss was rarely observed at loci on 9q and 10p and was not observed at loci on 3p, 3q, 4p, 5q, 12q, 14q, 18q, 22q, or Xp. In summary, clonal allelic loss of loci on chromosome arm 1p is a frequent feature of parathyroid adenomas, implying that inactivation of a tumor suppressor gene(s) on 1p commonly contributes to their pathogenesis.

Topics: Adenoma; Adolescent; Adult; Aged; Alleles; Chromosomes, Human, Pair 1; Cyclin D1; Cyclins; DNA; DNA, Neoplasm; Female; Follow-Up Studies; Gene Deletion; Gene Expression Regulation, Neoplastic; Gene Rearrangement; Genetic Markers; Heterozygote; Humans; Male; Middle Aged; Oncogene Proteins; Parathyroid Neoplasms; Transcriptional Activation

Topics: Adenoma; Chromosome Inversion; Chromosomes, Human, Pair 11; Cyclin D1; Cyclins; Gene Expression Regulation, Neoplastic; Gene Rearrangement; Genes, Retinoblastoma; Humans; Oncogene Proteins; Parathyroid Neoplasms; Proto-Oncogene Proteins

The D-type cyclins are among the candidate 'G1 cyclins' in higher eukaryotes that may regulate G1-S-phase progression. The human cyclin D1 gene, also known as PRAD1 (and previously as D11S287), is a putative proto-oncogene strongly implicated in several types of human tumors, including parathyroid adenomas, B-cell neoplasms (as the 'BCL-1 oncogene'), and breast and squamous cell cancers. The mechanism by which deregulated production of cyclin D1/PRAD1, and perhaps other D-type cyclins, contributes to tumor development is only beginning to be deciphered.

Topics: Adenoma; Breast Neoplasms; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Cell Transformation, Neoplastic; Cyclin D1; Cyclins; Gene Expression Regulation, Neoplastic; Humans; Leukemia, B-Cell; Lymphoma, B-Cell; Multigene Family; Oncogene Proteins; Parathyroid Neoplasms; Proto-Oncogene Mas; Proto-Oncogenes

Primary hyperparathyroidism (PHPT) is a common endocrinopathy for which several pathogenic mechanisms, including cyclin D1 overexpression, have been identified. Vitamin D nutritional status may influence parathyroid tumorigenesis, but evidence remains circumstantial. To assess the potential influence of vitamin D insufficiency/deficiency on initiation or progression of parathyroid tumorigenesis, we superimposed vitamin D insufficiency or deficiency on parathyroid tumor-prone parathyroid hormone-cyclin D1 transgenic mice. Mice were placed on diets containing either 2.75 IU/g, 0.25 IU/g, or 0.05 IU/g cholecalciferol, either prior to expected onset of PHPT or after onset of biochemical PHPT. When introduced early, superimposed vitamin D insufficiency/deficiency had no effect on serum calcium or on parathyroid gland growth. However, when introduced after the onset of biochemical PHPT, vitamin D deficiency led to larger parathyroid glands without differences in serum biochemical parameters. Our results suggest that low vitamin D status enhances proliferation of parathyroid cells whose growth is already being tumorigenically driven, in contrast to its apparent lack of direct proliferation-initiating action on normally growing parathyroid cells in this model. These results are consistent with the hypothesis that suboptimal vitamin D status may not increase incidence of de novo parathyroid tumorigenesis but may accelerate growth of a preexisting parathyroid tumor.

Topics: Animals; Carcinogenesis; Cell Transformation, Neoplastic; Cyclin D1; Mice; Mice, Transgenic; Parathyroid Glands; Parathyroid Hormone; Parathyroid Neoplasms; Vitamin D; Vitamin D Deficiency; Vitamins

The protein product of the cyclin D1 oncogene functions by activating partner cyclin-dependent kinases (cdk)4 or cdk6 to phosphorylate, thereby inactivating, the retinoblastoma protein pRB. Nonclassical, cdk-independent, functions of cyclin D1 have been described but their role in cyclin D1-driven neoplasia, with attendant implications for recently approved cdk4/6 chemotherapeutic inhibitors, requires further examination. We investigated whether cyclin D1's role in parathyroid tumorigenesis in vivo is effected primarily through kinase-dependent or kinase-independent mechanisms. Using a mouse model of cyclin D1-driven parathyroid tumorigenesis (PTH-D1), we generated new transgenic lines harboring a mutant cyclin D1 (KE) that is unable to activate its partner kinases. While this kinase-dead KE mutant effectively drove mammary tumorigenesis in an analogous model, parathyroid-overexpressed cyclin D1 KE mice did not develop the characteristic biochemical hyperparathyroidism or parathyroid hypercellularity of PTH-D1 mice. These results strongly suggest that in parathyroid cells, cyclin D1 drives tumorigenesis predominantly through cdk-dependent mechanisms, in marked contrast with the cdk-independence of cyclin D1-driven mouse mammary cancer. These findings highlight crucial tissue-specific mechanistic differences in cyclin D1-driven tumorigenesis, suggest that parathyroid/endocrine cells may be more tumorigenically vulnerable to acquired genetic perturbations in cdk-mediated proliferative control than other tissues, and carry important considerations for therapeutic intervention.

Topics: Adenoma; Animals; Cell Transformation, Neoplastic; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Hyperparathyroidism; Mice; Mice, Transgenic; Mutation; Parathyroid Neoplasms; Phosphorylation; Signal Transduction

Primary hyperparathyroidism is commonly caused by excess production of parathyroid hormone from sporadic parathyroid adenomas. However, the genetic architecture of sporadic primary hyperparathyroidism remains largely uncharacterized, especially in the Chinese population. To identify genetic abnormalities that may be involved in the etiology of sporadic parathyroid adenomas and to determine the mutation frequency of previously identified genes in the Chinese population, we performed whole-exome sequencing of 22 blood-tumor pairs from sporadic parathyroid adenomas. The most important finding is the recurrently mutated gene, ASXL3, which has never been reported in parathyroid tumors before. Moreover, we identified two different somatic mutations in the CDC73 gene and one somatic mutation in the EZH2 gene. The Y54X mutation in the CDC73 gene was previously identified in parathyroid carcinomas, which proved that parathyroid adenomas and carcinomas might possess similar molecular signatures. No mutations in the MEN1 or CCND1 genes were observed in our study. Thus, our data provide insights into the genetic pathogenesis of sporadic parathyroid adenomas and are valuable for the development of diagnostic and therapeutic approaches for sporadic primary hyperparathyroidism.

Topics: Adenoma; Adult; Aged; Asian People; Cyclin D1; DNA Mutational Analysis; Enhancer of Zeste Homolog 2 Protein; Exome Sequencing; Female; Humans; Hyperparathyroidism, Primary; Male; Middle Aged; Mutation; Parathyroid Neoplasms; Proto-Oncogene Proteins; Sequence Analysis, DNA; Transcription Factors; Tumor Suppressor Proteins

Cyclin D1, a G1-S phase regulator, is upregulated in parathyroid adenomas. Since cyclin-dependent kinase (CDK) inhibitors, CDKN2A and CDKN2B, and RASSF1A (Ras-association domain family 1, isoform A) are involved in G1-S phase arrest and act as potential tumor suppressor genes, we aimed to study potential methylation-mediated inactivation of these genes in parathyroid adenomas. Gene expressions of cyclin D1 (CCND1) and regulatory molecules (CDKN2A, CDKN2B and RASSF1A) was analysed in parathyroid adenoma tissues (n = 30). DNA promoter methylation of cyclin D1 regulators were assessed and correlated with clinicopathological features of the patients. Gene expression analysis showed a relative fold reductions of 0.35 for CDKN2A (p = 0.01), 0.45 for CDKN2B (P = 0.02), and 0.39 for RASSF1A (p < 0.01) in adenomatous compared to normal parathyroid tissue. There was an inverse relationship between the expressions of CDKN2A and CDKN2B with CCND1. In addition, the promoter regions of CDKN2A, CDKN2B, and of RASSF1A were significantly hyper-methylated in 50% (n = 15), 47% (n = 14), and 90% (n = 27) of adenomas respectively. In contrast, no such aberrant methylation of these genes was observed in normal parathyroid tissue. So, promoter hypermethylation is associated with down-regulation of CCND1 regulatory genes in sporadic parathyroid adenomas. This dysregulated cell cycle mechanism may contribute to parathyroid tumorigenesis.

Topics: Adenoma; Adolescent; Adult; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p15; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p18; DNA Methylation; Down-Regulation; Epigenesis, Genetic; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Parathyroid Neoplasms; Promoter Regions, Genetic; Sequence Analysis, DNA; Tumor Suppressor Proteins; Young Adult

Primary hyperparathyroidism is primarily due to a solitary parathyroid adenoma but multi-gland disease, parathyroid carcinoma, and ectopic parathyroid hormone production can occur. Although primary hyperparathyroidism mostly presents sporadically, strong familial predispositions also exist. Much is known about heritable genetic mutations responsible for these syndromes, including multiple endocrine neoplasia types 1 and 2A, hyperparathyroidism-jaw tumor syndrome, and familial hypocalciuric hypercalcemia. Acquired mutations in common sporadic hyperparathyroidism have also been discovered. Here we focus on the most common and well-established genetic drivers: 1) involvement of the oncogene cyclin D1 in human neoplasia was first established in parathyroid adenomas, followed by recognition of its importance in other tumor types including breast cancer and B-lymphoid malignancy; and 2) somatic mutation of the

Topics: Adenoma; Cyclin D1; Fibroma; Humans; Hyperparathyroidism; Hyperparathyroidism, Primary; Jaw Neoplasms; Parathyroid Neoplasms; Proto-Oncogene Proteins

The molecular bases for parathyroid carcinomas present in conjunction with sporadic primary hyperparathyroidism are not fully elucidated. Gene copy number variations (CNVs) play an important role in tumorigenesis. The aim of the current study was to explore whether the CNVs of specific tumor-associated genes are involved in parathyroid carcinogenesis.. A multiplex ligation-dependent probe amplification method was used to compare differences in copy number in 39 common tumor-associated genes among 7 patients with parathyroid carcinoma and 14 age- and sex-matched subjects with parathyroid adenoma.. It was shown that amplification of CCND1, a gene encoding cyclin D1, was more prevalent in parathyroid carcinomas than in adenomas (71 vs. 21 %, p = 0.056). This result was confirmed quantitatively by real-time polymerase chain reaction. Expression of CCND1 mRNA level was significantly higher in carcinomas than in adenomas (p = 0.003). Western blot and immunohistochemical analysis also demonstrated higher expression of CCND1 in carcinoma specimens than in adenoma samples.. It is thus inferred that gain in copy number of CCND1 is implicated in the molecular pathogenesis of parathyroid carcinoma.

Topics: Adenoma; Adult; Aged; Carcinoma; Cyclin D1; DNA Copy Number Variations; Female; Humans; Hyperparathyroidism, Primary; Male; Middle Aged; Multiplex Polymerase Chain Reaction; Parathyroid Neoplasms; Real-Time Polymerase Chain Reaction; RNA, Messenger

Parathyroid cancer is rare. Differentiating parathyroid carcinoma from degenerative changes at histopathology can be difficult and studies investigating the value of single immunohistochemical markers have had variable results. In this study we aimed to investigate whether a panel of immunohistochemistry markers could aid the diagnosis of parathyroid cancer.. All cases of parathyroid cancer at our institution from 1998 to 2012 were identified retrospectively. Cases were classified as definite cancers (those with evidence of metastatic spread) or histological cancers (those with features of carcinoma without evidence of metastasis). Controls with benign parathyroid disease were included for comparison. Immunohistochemistry for parafibromin, galectin-3, PGP9.5, Ki67, and cyclin D1 was analysed by an experienced endocrine pathologist.. There were 24 cases and 14 benign adenomas. Four cases had evidence of metastatic spread and 20 were diagnosed on histological criteria alone. Sixteen of the 24 cases had further surgery with ipsilateral thyroid lobectomy and 15 also had a prophylactic level VI lymph node dissection. Apart from one patient with distant metastases at presentation, none developed recurrence at follow-up (median = 38 months). Immunohistochemistry results associated with parathyroid cancer were seen in 11/24 parafibromin, 13/24 galectin-3, 8/24 PGP9.5, 5/24 Ki67, and 2/24 cyclin D1. None of the controls had immunohistochemical staining suggestive of cancer. Nineteen of the 24 patients had at least one immunohistochemical result associated with parathyroid cancer (sensitivity 79 %, specificity 100 %). Cyclin D1 did not suggest malignancy in any case that did not already have another abnormal marker, and so did not add value to the panel in this study.. A panel of immunohistochemistry (PGP9.5, galectin-3, parafibromin, and Ki67) is better than any single marker and can be used to supplement classical histopathology in diagnosing parathyroid cancer.

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Carcinoma; Case-Control Studies; Cyclin D1; Female; Galectin 3; Humans; Immunohistochemistry; Ki-67 Antigen; Male; Middle Aged; Neoplasm Proteins; Parathyroid Neoplasms; Retrospective Studies; Sensitivity and Specificity; Tumor Suppressor Proteins; Ubiquitin Thiolesterase

Primary hyperparathyroidism (PHPT) occurs sporadically, but occasionally it may be a feature of a familial condition, such as multiple endocrine neoplasia type 1 (MEN1), MEN2A, or the HPT-jaw tumor syndrome (HPT-JT), and familial hypocalciuric hypercalcemia/neonatal severe hyperparathyroidism (FHH/NSHPT). PHPT may also occur as familial isolated hyperparathyroidism (FIHP), and has been observed as a consequence of mutations in the CDKN1B gene (MEN4). Tumorigenesis in these conditions may be the result of protooncogene activation (e.g. RET in MEN2) or two-hit losses of a tumor suppressor (e.g. MEN1, HPT-JT). In patients with MEN1, HPT-JT or FHH/NSHPT, the hyperparathyroidism manifests at a younger age and affects both sexes equally. In MEN1, mutations of the MEN1 gene also cause enteropancreatic and anterior pituitary tumors. In MEN2, activating mutations in the RET protooncogene also cause medullary thyroid carcinoma and pheochromocytoma. In HPT-JT, mutations of CDC73/HRPT2 are associated with parathyroid carcinoma, but tumors of the kidneys and uterus are additional features. In some FIHP families, a CASR mutation may be identified. In parathyroid carcinoma, even if sporadic, molecular diagnostics for CDC73/HRPT2 should be considered, as it should be for younger patients. Further exploration of these hereditary syndromes may shed light on the molecular mechanisms giving rise to nonhereditary PHPT.

Topics: Cyclin D1; Cyclin-Dependent Kinase Inhibitor p27; Female; Humans; Hypercalcemia; Hyperparathyroidism, Primary; Infant, Newborn; Infant, Newborn, Diseases; Jaw Neoplasms; Loss of Heterozygosity; Male; Multiple Endocrine Neoplasia Type 1; Multiple Endocrine Neoplasia Type 2a; Parathyroid Neoplasms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-ret; Receptors, Calcium-Sensing; Tumor Suppressor Proteins

To explore underlying molecular mechanisms in the pathogenesis of symptomatic sporadic primary hyperparathyroidism (PHPT).. Forty-one parathyroid adenomas from patients with symptomatic PHPT and ten normal parathyroid glands either from patients with PHPT (n=3) or from euthyroid patients without PHPT during thyroid surgery (n=7) were analyzed for vitamin D receptor (VDR), calcium-sensing receptor (CASR), cyclin D1 (CD1), and parathyroid hormone (PTH) expressions. The protein expressions were assessed semiquantitatively by immunohistochemistry, based on percentage of positive cells and staining intensity, and confirmed by quantitative real-time PCR.. Immunohistochemistry revealed significant reductions in VDR (both nuclear and cytoplasmic) and CASR expressions and significant increases in CD1 and PTH expressions in adenomatous compared with normal parathyroid tissue. Consistent with immunohistochemistry findings, both VDR and CASR mRNAs were reduced by 0.36- and 0.45-fold change (P<0.001) and CD1 and PTH mRNAs were increased by 9.4- and 17.4-fold change respectively (P<0.001) in adenomatous parathyroid tissue. PTH mRNA correlated with plasma PTH (r=0.864; P<0.001), but not with adenoma weight, while CD1 mRNA correlated with adenoma weight (r=0.715; P<0.001). There were no correlations between VDR and CASR mRNA levels and serum Ca, plasma intact PTH, or 25-hydroxyvitamin D levels. In addition, there was no relationship between the decreases in VDR and CASR mRNA expressions and the increases in PTH and CD1 mRNA expressions.. The expression of both VDR and CASR are reduced in symptomatic PHPT in Asian Indians. In addition, CD1 expression was greatly increased and correlated with adenoma weight, implying a potential role for CD1 in adenoma growth and differential clinical expression of PHPT.

Topics: Adenoma; Adolescent; Adult; Aged; Child; Cyclin D1; DNA, Complementary; Female; Gene Expression Regulation, Neoplastic; Humans; Hyperparathyroidism, Primary; Immunohistochemistry; India; Male; Middle Aged; Parathyroid Glands; Parathyroid Hormone; Parathyroid Neoplasms; Real-Time Polymerase Chain Reaction; Receptors, Calcitriol; Receptors, Calcium-Sensing; RNA, Messenger; Up-Regulation; White People

Genetic abnormalities, such as those of multiple endocrine neoplasia type 1 (MEN1) and Cyclin D1 (CCND1) genes, occur in <50% of nonhereditary (sporadic) parathyroid adenomas.. To identify genetic abnormalities in nonhereditary parathyroid adenomas by whole-exome sequence analysis.. Whole-exome sequence analysis was performed on parathyroid adenomas and leukocyte DNA samples from 16 postmenopausal women without a family history of parathyroid tumors or MEN1 and in whom primary hyperparathyroidism due to single-gland disease was cured by surgery. Somatic variants confirmed in this discovery set were assessed in 24 other parathyroid adenomas.. Over 90% of targeted exons were captured and represented by more than 10 base reads. Analysis identified 212 somatic variants (median eight per tumor; range, 2-110), with the majority being heterozygous nonsynonymous single-nucleotide variants that predicted missense amino acid substitutions. Somatic MEN1 mutations occurred in six of 16 (∼35%) parathyroid adenomas, in association with loss of heterozygosity on chromosome 11. However, no other gene was mutated in more than one tumor. Mutations in several genes that may represent low-frequency driver mutations were identified, including a protection of telomeres 1 (POT1) mutation that resulted in exon skipping and disruption to the single-stranded DNA-binding domain, which may contribute to increased genomic instability and the observed high mutation rate in one tumor.. Parathyroid adenomas typically harbor few somatic variants, consistent with their low proliferation rates. MEN1 mutation represents the major driver in sporadic parathyroid tumorigenesis although multiple low-frequency driver mutations likely account for tumors not harboring somatic MEN1 mutations.

Topics: Adenoma; Aged; Aged, 80 and over; Cyclin D1; DNA Mutational Analysis; Exome; Female; Genetic Variation; Humans; Hyperparathyroidism, Primary; Male; Middle Aged; Multiple Endocrine Neoplasia Type 1; Parathyroid Neoplasms; Shelterin Complex; Telomere-Binding Proteins

Parathyroid adenomas can contain clonal rearrangements of chromosome 11 that activate the cyclin D1 oncogene through juxtaposition with the PTH gene. Here we describe such a chromosomal rearrangement whose novel features provide clues to locating elusive cis-regulatory elements in the PTH gene and also expand the physical spectrum of pathogenetic breakpoints in the cyclin D1 gene region. Southern blot analyses of the parathyroid adenoma revealed rearrangement in the PTH gene locus. Analysis of rearranged DNA clones that contained the breakpoint, obtained by screening a tumor genomic library, pinpointed the breakpoint in the PTH locus 3.3 kb upstream of the first exon. Accordingly, highly conserved distal elements of the PTH 5' regulatory region were rearranged at the breakpoint approximately 450 kb upstream of the cyclin D1 oncogene, resulting in overexpression of cyclin D1 mRNA. Thus, PTH-cyclin D1 gene rearrangement breakpoints in parathyroid tumors can be located far from those previously recognized. In addition to expanding the molecular spectrum of pathogenetic chromosomal lesions in this disease, features of this specific rearrangement reinforce the existence of one or more novel cis-enhancer/regulatory elements for PTH gene expression and narrow their location to a 1.7-kb DNA segment in the distal PTH promoter.

Topics: Alleles; Binding Sites; Chromosome Breakpoints; Chromosomes, Human, Pair 11; Conserved Sequence; Cyclin D1; Gene Expression Regulation, Neoplastic; Gene Rearrangement; Genetic Loci; Humans; In Situ Hybridization, Fluorescence; Interphase; Male; Organ Specificity; Parathyroid Hormone; Parathyroid Neoplasms; Regulatory Sequences, Nucleic Acid; Reverse Transcriptase Polymerase Chain Reaction; Species Specificity; Transcription Factors

HRPT2 gene mutations are associated with parathyroid carcinomas, and absence of parafibromin immunoreactivity has been suggested as a diagnostic marker of malignancy. The aim of our study was to extend parafibromin studies in a series of benign and malignant parathyroid tumors and cross-validate the results of immunohistochemistry with those of HRPT2 analysis.. We performed parafibromin and cyclin D1 immunostaining and HRPT2 gene analysis using loss of heterozygosity studies and sequencing analysis in parathyroid specimens from 11 patients with carcinoma (eleven primary tumors, one skin, and four lung metastases), 22 with sporadic adenomas, and 4 with atypical adenomas.. Ten out of eleven parathyroid cancers were negative for parafibromin staining and showed HRPT2 gene abnormalities. The remaining sample was negative for immunostaining and genetic analyses. All but one sporadic adenomas showed parafibromin immunoreactivity and no HRPT2 gene abnormalities. The sample with negative immunostaining carried an HRPT2 mutation. Two atypical adenomas were positive and two negative with parafibromin staining. No HRPT2 abnormalities were found in these samples. Cyclin D1 expression was heterogeneous and there was no relationship between expression/expression level of cyclin D1 and parafibromin expression.. We have shown that negative parafibromin staining is almost invariably associated with HRPT2 mutations and confirm that loss of parafibromin staining strongly predicts parathyroid malignancy. In clinical practice, these tests could be particularly useful in the subset of parathyroid tumors with equivocal histological examination. However, their diagnostic value in this setting remains to be proven.

Topics: Adenoma; Adult; Carcinoma; Cyclin D1; DNA, Neoplasm; Female; Humans; Immunohistochemistry; Loss of Heterozygosity; Male; Middle Aged; Parathyroid Neoplasms; Predictive Value of Tests; Sensitivity and Specificity; Sequence Analysis, DNA; Tumor Suppressor Proteins

The study investigated cyclin D1 regulation by growth factors and calcium sensing receptor (CaSR) in human tumoral parathyroid cells. Basic fibroblast and epidermal growth factors increased cyclin D1 and phosphorylated extracellular signal-regulated kinases (pERK1/2) levels that were both efficiently inhibited by CaSR agonists. By contrast, in growth factors-free medium cyclin D1 levels were either unaffected or stimulated by CaSR activation independently from ERK1/2 pathway. Transforming growth factor beta (TGFbeta) reduced cyclin D1 levels in the majority of tumors, this effect being not influenced by CaSR activation and menin expression levels. In conclusion, in parathyroid tumors cyclin D1 expression was modulated by growth factors and CaSR activation. These data further support the oncogenic role of cyclin D1, which resulted to be target for stimulation by bFGF and EGF and inhibition by CaSR and TGFbeta signalling in the parathyroid.

Topics: Cyclin D1; DNA Methylation; Gene Expression Regulation, Neoplastic; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Models, Biological; Parathyroid Glands; Parathyroid Neoplasms; Phosphorylation; Proto-Oncogene Proteins; Receptors, Calcium-Sensing; Receptors, Retinoic Acid; Signal Transduction; Transforming Growth Factor beta

Inactivation of the hyperparathyroidism-jaw tumour syndrome (HPT- JT) gene, HRPT2, was recently established as a genetic mechanism in the development of parathyroid tumours. Its encoded protein parafibromin has tumour-suppressor properties that play an important role in tumour development in the parathyroids, jaws and kidneys. Inactivating HRPT2 mutations are common in HPT- JT and parathyroid carcinomas, and have been described in a few cases of parathyroid adenomas with cystic features. In this study, 46 cases of cystic parathyroid adenomas previously investigated for HRPT2 mutations were characterized with regard to MEN1 gene mutations, cyclin D1 expression and parafibromin expression. In normal tissues and cell lines, parafibromin was ubiquitously expressed. Furthermore, parafibromin was detected as a dominating nuclear and a weaker cytoplasmic signal in transfected cell lines. In the three parathyroid tumours with inactivating HRPT2 mutations parafibromin expression was not detectable, and in one of two cases with aberrantly sized parafibromin the protein was delocalized. Both high and low cyclin D1 levels were found among HRPT2-mutated and -unmutated tumours, suggesting that these events are not mutually exclusive in parathyroid tumour development. The presented data suggest that in the majority of benign parathyroid tumours the expression of parafibromin remains unaltered, while the loss of parafibromin expression is strongly indicative of gene inactivation through mutation of the HRPT2 gene.

Topics: Adenoma; Adult; Aged; Animals; Chlorocebus aethiops; COS Cells; Cyclin D1; Female; HeLa Cells; Humans; Immunohistochemistry; Loss of Heterozygosity; Male; Middle Aged; Mutation; Parathyroid Neoplasms; Proto-Oncogene Proteins; RNA, Messenger; Tumor Suppressor Proteins

Parafibromin is the 531-amino-acid protein product encoded by HRPT2, a putative tumor suppressor gene recently implicated in the autosomal dominant hyperparathyroidism-jaw tumor familial cancer syndrome, sporadic parathyroid cancer, and a minority of families with isolated hyperparathyroidism. Parafibromin contains no identified functional domains but bears sequence homology to Cdc73p, a budding yeast protein component of the RNA polymerase II-associated Paf1 complex. This study addressed the expression and functional properties of human parafibromin. A survey of human and mouse tissues analysed with polyclonal antibodies to parafibromin showed specific immunoreactivity in adrenal and parathyroid glands, kidney, heart, and skeletal muscle. Subcellular fractionation and laser confocal microscopy of normal human parathyroid gland demonstrated expression of parafibromin in both the cytoplasmic and nuclear compartments. Parafibromin was expressed in four parathyroid adenomas but was absent from two parathyroid carcinomas. Transient overexpression of wild-type parafibromin, but not its Leu64Pro missense mutant implicated in parathyroid cancer and familial isolated hyperparathyroidism, inhibited cell proliferation, and blocked expression of cyclin D1, a key cell cycle regulator previously implicated in parathyroid neoplasia. These results demonstrate that human parafibromin is a nucleocytoplasmic protein with functions consistent with its postulated role as a tumor suppressor protein.

Topics: Adenoma; Animals; Carcinoma; Cell Nucleus; Cell Proliferation; Chlorocebus aethiops; COS Cells; Cyclin D1; Cytoplasm; Down-Regulation; Humans; Mice; Mutation, Missense; Parathyroid Glands; Parathyroid Neoplasms; Proteins; Transfection; Tumor Suppressor Proteins

Somatic deletion of chromosome 11q13 is the most frequent genetic aberration in parathyroid adenoma. To gain further insight into the genetic etiology of parathyroid tumor development, we examined a comprehensive gene expression profile of parathyroid adenomas and normal parathyroid tissues. The results were then evaluated with respect to differences between adenomas and normal parathyroid tissue, and to the presence of loss of heterozygosity (LOH) in chromosomal region 11q13.. Sporadic parathyroid adenomas and normal parathyroids were hybridized against HG-U95Av2 oligonucleotide arrays (Affymetrix) containing a total of 12,625 probe sets. Quantitative real-time PCR (QRT-PCR) was performed in a larger series of parathyroid adenomas, in order to con-firm the microarray results.. Cyclin D1 and c-Jun showed increased expression in adenomas vs normal parathyroids by microarray analysis and QRT-PCR, suggesting an oncogenic role of these genes in parathyroid tumor development. At unsupervised hierarchical clustering, the adenomas fell into two groups: Group I adenomas were characterized by 11q13 LOH, while Group II adenomas lacked this abnormality. In addition, a t-test analysis identified largely non-overlapping genes with differential expression in the tumors subgroups; e.g. in Group I tumors the putative oncogene ENC 1 was found highly over-expressed vs Group II adenomas.. The microarray analyses revealed partly distinctive and partly common expression profiles in parathyroid adenomas with and without 11q13 LOH. In addition, approximately half of the under-expressed genes were mapped to chromosome 11, in agreement with a dose effect following loss of this chromosome.

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Case-Control Studies; Chromosomes, Human, Pair 11; Cyclin D1; Female; Gene Expression; Gene Expression Profiling; Genes, jun; Humans; Loss of Heterozygosity; Male; Microarray Analysis; Middle Aged; Multigene Family; Parathyroid Neoplasms; Reverse Transcriptase Polymerase Chain Reaction

Previous studies indicate that nuclear factor kappaB (NF-kappaB) transcription factor is deregulated and overexpressed in several human neoplasias. The aim of this study was to test the hypothesis that the NF-kappaB pathway may be involved in parathyroid tumorigenesis. For this purpose, we determined the level of NF-kappaB activity, evaluated as phosphorylation of the transcription subunit p65, its modulation by specific and non-specific agents and its impact on cyclin D1 expression. Phosphorylated p65 levels present in parathyroid neoplasias (n = 13) were significantly lower than those found in normal tissues (n = 3; mean optical density (OD) 0.19 +/- 0.1 vs 0.4 +/- 0.1, P = 0.007), but there was no significant difference between adenomas and secondary and multiple endocrine neoplasia type 1 (MEN1)-related hyperplasia. Conversely, MEN2A (Cys634Arg)-related parathyroid samples showed extremely high levels of phosphorylated p65 that exhibited a nuclear localization at immunohistochemistry (n = 3). Phosphorylated p65 levels negatively correlated with menin expression (r(2) = 0.42, P = 0.05). Tumor necrosis factor-alpha (TNFalpha) caused a significant increase in phosphorylated p65 levels (183 +/- 13.8% of basal) while calcium sensing receptor (CaR) agonists exerted a significant inhibition (19.2 +/- 3.3% of basal). Although TNFalpha was poorly effective in increasing cyclin D1 expression, NF-kappaB blockade by the specific inhibitor BAY11-7082 reduced FCS-stimulated cyclin D1 by about 60%. Finally, the inhibitory effects of CaR and BAY11-7082 on cyclin D1 expression were not additive - by blocking NF-kappaB CaR activation did not induce a further reduction in cyclin D1 levels. In conclusion, the study demonstrated that in parathyroid tumors: (1) p65 phosphorylation was dramatically increased by RET constitutive activation and was negatively correlated with menin expression, (2) p65 phosphorylation was increased and reduced by TNFalpha and CaR agonists respectively, and (3) blockade of the NF-kappaB pathway caused a significant decrease in cyclin D1 expression.

Topics: Cyclin D1; Humans; Immunohistochemistry; NF-kappa B; Nitriles; Parathyroid Glands; Parathyroid Neoplasms; Phosphorylation; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-ret; Sulfones; Transcription Factor RelA; Tumor Necrosis Factor-alpha

Malignant transformation of parathyroid tumours is rare. Nevertheless, this small subset of malignant tumours often creates diagnostic and therapeutic problems. In this work, the morphological characteristics of 26 primary parathyroid carcinomas and seven metastases have been studied. Furthermore, immunohistochemical expression profiles for the calcium sensing receptor (CASR), cyclin D1 (CCND1), and Ki-67 were determined for parathyroid carcinomas and compared with adenomas and hyperplasias using a tissue microarray. Loss of heterozygosity (LOH) of the chromosome 1q region containing the HRPT2 gene and chromosome 11q (MEN1) was determined in the carcinomas. In contrast to the adenomas and hyperplasias, 31% of carcinomas demonstrated down-regulation of CASR. A significant correlation was found between CASR expression and the Ki-67 proliferation index. Chromosome 1q and chromosome 11q LOH were found in 12 of 22 (55%) and 11 of 22 (50%) carcinomas tested, respectively. Combined 1q and 11q LOH was seen in 8 of 22 (36%) carcinomas, in contrast to the low percentage of LOH reported in both regions in adenomas. In conclusion, this study demonstrates that combined 1q and 11q LOH in parathyroid tumours is suggestive of malignant behaviour. Strong down-regulation of the CASR protein is seen in a proportion of parathyroid carcinomas with a high proliferation index.

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Carcinoma; Chromosomes, Human, Pair 1; Chromosomes, Human, Pair 11; Cyclin D1; Female; Gene Expression Regulation, Neoplastic; Humans; Hyperplasia; Immunohistochemistry; Ki-67 Antigen; Loss of Heterozygosity; Lymphatic Metastasis; Male; Middle Aged; Oligonucleotide Array Sequence Analysis; Parathyroid Glands; Parathyroid Neoplasms; Receptors, Calcium-Sensing

Parathyroid adenomas are benign uniglandular tumors and are the most common cause of primary hyperparathyroidism. Several genetic changes in parathyroid tumors, including inactivation of tumor suppressor genes, activation of oncogenes and loss of heterozygosity at several chromosomal loci, have been reported. In this study, we analyzed the status of cyclin D1 and beta-catenin in 24 cases of parathyroid adenoma. Immunohistochemistry of cyclin D1 showed positive staining in 9 (37.5%) of the 24 parathyroid adenomas. The status of beta-catenin, which has recently been identified as a regulator of cyclin D1 transcription, was examined by direct sequencing of exon 3 of the beta-catenin gene and immunohistochemistry of beta-catenin protein, but neither mutation nor accumulation of beta-catenin was detected in any of the cases. These results indicate that cyclin D1 is frequently accumulated in parathyroid adenomas, independently of dysfunction in the Wnt signaling pathway.

Topics: Adenoma; beta Catenin; Cell Adhesion; Cyclin D1; Cytoskeletal Proteins; DNA Mutational Analysis; Exons; Humans; Immunohistochemistry; Mutation; Parathyroid Neoplasms; Signal Transduction; Trans-Activators; Transcription, Genetic

Hyperparathyroidism may result from parathyroid hyperplasia or adenoma, or rarely from parathyroid carcinoma. Pericentromeric inversion of chromosome 11 that results in activation of the P:RAD1/cyclin D1 gene and tumor suppressor gene loss have been described as genetic abnormalities in the evolution of parathyroid neoplasms. We studied tissue samples taken from primary parathyroid hyperplasia, parathyroid adenoma, and histologically normal parathyroid tissue by comparative genomic hybridization, fluorescent in situ hybridization, and immunohistochemistry for cyclin D1. DNA copy number changes were infrequent in primary hyperplasia (4 of 24, 17%), but common in adenomas (10 of 16, 63%; P: = 0.0059). The most common change was deletion of the entire chromosome 11 or a part of it, with a minimal common region at 11q23. This change was present in five (31%) adenomas and two (8%) primary hyperplasias. Fluorescent in situ hybridization confirmed the presence of both MEN1 alleles located at 11q13 despite deletion of 11q23 in all three cases studied. Cyclin D1 was overexpressed in six (40%) of the 15 adenomas studied, whereas none of the 27 hyperplasias (P: = 0.0010) nor the five histologically normal tissue samples overexpressed cyclin D1. Either DNA copy number loss or cyclin D1 overexpression was present in 13 (81%) of the 16 adenomas. We conclude that DNA copy number loss and cyclin D1 overexpression are common in parathyroid adenomas. The region 11q23 is frequently lost in parathyroid adenomas and occasionally in parathyroid hyperplasias, and this suggests the possibility that a tumor suppressor gene that is important in their pathogenesis is present on 11q23.

Topics: Adenoma; Adult; Aged; Chromosomes, Human, Pair 11; Cyclin D1; Female; Gene Deletion; Gene Dosage; Humans; In Situ Hybridization, Fluorescence; Male; Middle Aged; Nucleic Acid Hybridization; Parathyroid Neoplasms

The relationship between abnormal cell proliferation and aberrant control of hormonal secretion is a fundamental and poorly understood issue in endocrine cell neoplasia. Transgenic mice with parathyroid-targeted overexpression of the cyclin D1 oncogene, modeling a gene rearrangement found in human tumors, were created to determine whether a primary defect in this cell-cycle regulator can cause an abnormal relationship between serum calcium and parathyroid hormone response, as is typical of human primary hyperparathyroidism. We also sought to develop an animal model of hyperparathyroidism and to examine directly cyclin D1's role in parathyroid tumorigenesis. Parathyroid hormone gene regulatory region--cyclin D1 (PTH--cyclin D1) mice not only developed abnormal parathyroid cell proliferation, but also developed chronic biochemical hyperparathyroidism with characteristic abnormalities in bone and, notably, a shift in the relationship between serum calcium and PTH. Thus, this animal model of human primary hyperparathyroidism provides direct experimental evidence that overexpression of the cyclin D1 oncogene can drive excessive parathyroid cell proliferation and that this proliferative defect need not occur solely as a downstream consequence of a defect in parathyroid hormone secretory control by serum calcium, as had been hypothesized. Instead, primary deregulation of cell-growth pathways can cause both the hypercellularity and abnormal control of hormonal secretion that are almost inevitably linked together in this common disorder.

Topics: Adenoma; Animals; Bone and Bones; Calcium; Calcium-Binding Proteins; Chromosome Aberrations; Chromosome Disorders; Cyclin D1; Gene Rearrangement; Humans; Hyperparathyroidism; Mice; Mice, Transgenic; Parathyroid Hormone; Parathyroid Neoplasms

In primary hyperparathyroidism, certain genetic abnormalities responsible for parathyroid tumorigenesis are proposed, and it has been reported that the overexpression of PRAD1/cyclin D1 induced by a DNA rearrangement of the parathyroid hormone (PTH) gene is one of the genetic disorders in a number of primary parathyroid adenomas. However, in secondary hyperparathyroidism caused by uremia, the mechanism of monoclonal proliferation in nodular parathyroid hyperplasia is not well understood. To elucidate the mechanism, we examined the expression of PRAD1/cyclin D1, retinoblastoma gene products, and Ki67 in primary adenoma and secondary hyperplasia.. In adenomas (N = 15) and associated glands (N = 7) with normal histology obtained from patients with primary hyperparathyroidism and in diffuse (N = 14), multinodular (N = 58), and single nodular (N = 28) glands from patients who underwent parathyroidectomy for renal hyperparathyroidism, the expression of these cell cycle regulators was evaluated by immunohistochemical technique. A labeling index was used to define the proportion of cells with positive nuclear staining by each antibody.. In 6 out of 15 (40%) primary adenomas, PRAD1/cyclin D1 was overexpressed (a labeling index of more than 500), possibly because of the PTH gene rearrangement, but not in secondary hyperplasia, including single nodular glands. Compared with diffuse hyperplasia, nodular hyperplasia showed a significantly higher expression of PRAD1/cyclin D1 (P < 0.05), retinoblastoma gene products (P < 0.05), and Ki67 (P < 0.05). However, no statistically significant correlation between the expression of PRAD1/cyclin D1 and that of Ki67 was observed in both primary adenoma and secondary hyperplasia.. These results suggest that in secondary hyperplasia caused by uremia, at least remarkable overexpression of PRAD1/cyclin D1 induced by PTH gene rearrangement may be not the major genetic abnormality responsible for tumorigenesis. Heterogenous genetic changes seem to contribute to monoclonal proliferation of parathyroid cells induced by the expression of PRAD1/cyclin D1 or by some other mechanism independent of the amplification of the proto-oncogene.

Topics: Adenoma; Biomarkers, Tumor; Cell Nucleus; Cyclin D1; Humans; Hyperplasia; Immunohistochemistry; Ki-67 Antigen; Kidney Failure, Chronic; Middle Aged; Parathyroid Glands; Parathyroid Neoplasms; Proto-Oncogene Mas; Retinoblastoma Protein

In this study, we assessed the frequency of cyclin D1 protein expression in normal and neoplastic parathyroid tissue (10 parathyroid carcinomas, 28 adenomas, 18 hyperplasias, and 32 normal parathyroid glands) with use of a monoclonal anticyclin D1 antibody and a heat-induced epitope retrieval method. Overexpression of cyclin D1 was identified in 10 (91%) of 11 biopsy specimens from 10 patients with parathyroid carcinomas and in 11 (39%) of 28 parathyroid adenomas. In addition, 11 (61%) of 18 cases of parathyroid hyperplasia also expressed cyclin D1 protein, an observation not reported previously. These results confirm the high frequency of cyclin D1 expression in parathyroid carcinomas and adenomas. In addition, the results of this study indicate that overexpression of cyclin D1 protein is not limited to neoplastic proliferations of parathyroid tissue but is also seen in non-neoplastic proliferations of parathyroid gland. Cyclin D1 protein expression was rarely (<6%) present in normal parathyroid tissue.

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Biopsy; Cyclin D1; Female; Humans; Hyperplasia; Immunohistochemistry; Male; Middle Aged; Parathyroid Glands; Parathyroid Neoplasms

The cyclin D1 (PRAD1) oncogene is rearranged with the PTH gene and is transcriptionally activated in a subset of parathyroid adenomas. Because of heterogeneity in rearrangement breakpoints, the true percentage of adenomas with cyclin D1 deregulation is unknown. Overexpression of the cyclin D1 protein in parathyroid adenomas appears to be a unifying consequence of all cyclin D1 gene rearrangements and can, therefore, be examined to more comprehensively identify adenomas in which cyclin D1 is pathogenetically important. We studied cyclin D1 expression in 65 parathyroid adenomas (from 64 patients), 51 normal parathyroid glands (from the same patients), and 4 parathyroid carcinoma specimens (from 3 patients) using a microwave-enhanced immunohistochemical method and affinity-purified cyclin D1 polyclonal antiserum. When available, data on adenoma mass, intact PTH level, and concurrent serum calcium level were also collected. Twelve of the 65 adenomas (18%) showed diffuse nuclear staining of approximately 30-70% of the tumor cells. All 51 normal glands were negative, except 1 gland that showed scattered cells ( < 10%) with positive nuclear staining. In addition, scattered positive cells were seen in the compressed rim of histologically normal parathyroid tissue surrounding 2 adenomas that were cyclin D1 negative. No significant differences in adenoma mass, intact PTH levels, or concurrent calcium levels were found between positive and negative tumors. Two of 4 parathyroid carcinoma specimens from 2 of 3 patients showed strong nuclear staining for cyclin D1. Overexpression of the cyclin D1 oncogene in 18% of our cases, due to the cyclin D1/PTH translocation and/or other mechanisms, suggests that overexpressed cyclin D1 plays a role in the pathogenesis of a much larger proportion of parathyroid adenomas than previously appreciated. Cyclin D1 overexpression is a feature of typical parathyroid adenomas and is not confined to unusually large, symptom-causing adenomas as had been suggested by early DNA studies. Although only three patients with parathyroid carcinoma were studied, two of the patients' tumors stained for cyclin D1, raising the possibility that the frequency of cyclin D1 overexpression may be even greater in carcinomas. Cyclin D1 overexpression appears to highlight a central pathway in parathyroid neoplasia.

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Calcium; Cyclin D1; Cyclins; Female; Gene Expression; Humans; Immunoenzyme Techniques; Male; Middle Aged; Oncogene Proteins; Parathyroid Hormone; Parathyroid Neoplasms

PRAD1 (cyclin D1) has been implicated in the molecular pathogenesis of a variety of tumors, including parathyroid adenomas, t(11;14)-bearing B-lymphoid tumors, and breast cancer. The sequence of the overexpressed PRAD1 genes has been directly analyzed in only two tumor specimens, a benign parathyroid adenoma and a malignant centrocytic lymphoma. Thus, little is known about PRAD1 sequence in the vast majority of human primary tumors, including breast cancers. Using single-strand conformational polymorphism (SSCP) analysis, we have examined the coding region of the PRAD1 gene in 30 primary breast cancers and 25 parathyroid adenomas. Polymerase chain reaction (PCR)-SSCP analysis of the coding region of exons 1-5 of the PRAD1 gene did not reveal any tumor-specific mutations. During the course of screening for mutations, we found and established the sequence variants of a new DNA polymorphism at codon 241 within exon 4 of the PRAD1 gene. Since this polymorphism is located within the coding region of the PRAD1 gene, it will allow determination of allele-specific expression of the gene and the detection of allele imbalance. At least in breast and parathyroid neoplasms, overexpression of the wild-type PRAD1 sequence, rather than point mutational activation, appears to be the predominant mechanism by which PRAD1 exerts its oncogenic action.

Topics: Adenoma; Base Sequence; Breast Neoplasms; Cyclin D1; Cyclins; Exons; Humans; Molecular Sequence Data; Oligonucleotide Probes; Oncogene Proteins; Oncogenes; Parathyroid Neoplasms; Point Mutation; Polymorphism, Genetic

Topics: Alleles; Carcinoma; Cyclin D1; Cyclins; Gene Deletion; Genes, Retinoblastoma; Humans; Mutation; Oncogene Proteins; Parathyroid Neoplasms

PRAD1 (previously D11S287) is a putative proto-oncogene at 11q13, activated by overexpression through gene rearrangement or gene amplification in several types of human tumors including parathyroid adenomas, centrocytic lymphomas and other B-cell tumors with t(11;14), and breast cancers. PRAD1 (also CCND1) encodes cyclin D1, which may regulate the G1-S phase transition in the cell cycle. Here, we report the cloning and characterization of the chromosomal PRAD1/cyclin D1 gene and the sequence of its promoter region. The gene spans about 15 kb and has 5 exons; its promoter region has Sp1 binding sites and no obvious TATA box, characteristics of housekeeping genes and growth-regulating genes. Furthermore, an E2F binding motif present close to the major transcription start site may be involved in cell cycle-dependent expression of this gene. We also report the sequence of DNAs spanning joining regions of a reciprocal parathyroid hormone/PRAD1 gene rearrangement in a parathyroid adenoma. Comparison with normal sequences suggests that the rearrangement was not a simple break-and-ligate event, but rather involved multiple steps, including two microdeletions and a microinversion. Very short sequences conserved near the breakpoints and symmetrical elements in the eventually inverted DNA segment might have played a role in this illegitimate complex recombination, which may have similarities with a constitutional translocation in Duchenne muscular dystrophy.

Topics: Adenoma; Amino Acid Sequence; Base Sequence; Cloning, Molecular; Cyclin D1; Cyclins; DNA, Neoplasm; Gene Rearrangement; Humans; Molecular Sequence Data; Oncogene Proteins; Parathyroid Hormone; Parathyroid Neoplasms; Promoter Regions, Genetic; Proto-Oncogene Mas; Proto-Oncogenes; Sequence Homology, Nucleic Acid

PRAD1 (cyclin D1) is a recently identified member of the family of cyclin genes, believed to play roles in regulating transitions through the cell cycle. The PRAD1 gene, located at 11q13, has been implicated in the pathogenesis of a variety of tumors, including parathyroid adenomas, t(11;14) bearing B-lymphoid tumors (particularly centrocytic lymphomas) where it is highly likely to be the BCL1 oncogene, and possibly in breast carcinomas and squamous cell cancers of the head and neck as well. PRAD1's tumorigenic influence appears to be effected through overexpression of its normal-sized transcript, but it has not been established whether the transcript's coding sequence is normal or contains oncogenic mutations. We have sequenced the coding region of the overexpressed PRAD1 transcript from two primary tumors with clonal PRAD1 region rearrangements: a benign parathyroid adenoma and a malignant centrocytic lymphoma. Each sequence is identical to the normal PRAD1 cDNA sequence, and presumably encodes normal PRAD1 protein. Thus, PRAD1 likely functions as a direct-acting oncogene whose rearrangement in tumors leads to overexpression or deregulated expression of its normal protein product.

Topics: Adenoma; Base Sequence; Cyclin D1; Cyclins; Gene Expression; Gene Rearrangement; Humans; Lymphoma; Molecular Sequence Data; Oncogene Proteins; Oncogenes; Parathyroid Neoplasms

We have previously identified a candidate oncogene (PRAD1 or D11S287E) on chromosome 11q13 which is clonally rearranged with the parathyroid hormone locus in a subset of benign parathyroid tumours. We now report that a cloned human placental PRAD1 complementary DNA encodes a protein of 295 amino acids with sequence similarities to the cyclins. Cyclins can form a complex with and activate p34cdc2 protein kinase, thereby regulating progress through the cell cycle. PRAD 1 messenger RNA levels vary dramatically across the cell cycle in HeLa cells. Addition of the PRAD1 protein to interphase clam embryo lysates containing inactive p34cdc2 kinase and lacking endogenous cyclins allows it to be isolated using beads bearing p13suc1, a yeast protein that binds cdc2 and related kinases with high affinity and coprecipitates kinase-associated proteins. Addition of PRAD1 also induces phosphorylation of histone H1, a preferred substrate of cdc2. These data suggest that PRAD1 encodes a novel cyclin whose overexpression may play an important part in the development of various tumours with abnormalities in 11q13.

Topics: Adenoma; Amino Acid Sequence; Animals; Base Sequence; Bivalvia; Cell Cycle; Chromosomes, Human, Pair 11; Cyclin D1; Cyclins; DNA; Gene Expression; Humans; Molecular Sequence Data; Oncogene Proteins; Oncogenes; Parathyroid Neoplasms; Proto-Oncogene Proteins; RNA, Messenger; Transfection

Topics: Adenoma; Amino Acid Sequence; Animals; Cell Cycle; Cyclin D1; Cyclins; DNA, Neoplasm; Humans; Molecular Sequence Data; Oncogene Proteins; Oncogenes; Parathyroid Neoplasms; Sequence Homology, Nucleic Acid