cyclin-d1 and Fibrocystic-Breast-Disease

Cyclin D-1 protein over-expression and/or gene amplification have been shown to be frequent events in subsets of breast carcinomas. Cyclin D-1 is generally considered as a weak oncogene, and its over-expression has been shown to occur in occasional benign breast lesions. In a previous series, we have shown that cyclin D-1 was over-expressed in subsets of apocrine metaplasia (APM) and apocrine adenosis (AA) of the breast and that such over-expression was mostly associated with a significant increase in the proliferative capacity of these lesions. We examined the mechanisms involved in cyclin D-1 over-expression in apocrine lesions. A total of 41 cases were analysed in this study. The cases were divided into: 18 cases of APM and 23 cases of AA. All cases analysed had been previously analysed by immunohistochemistry, and all showed over-expression of the cyclin D-1 protein. Fluorescence in situ hybridisation (FISH) was performed using a dual cyclin D-1 (spectrum orange)/chromosome 11 centromere (spectrum green) DNA probe. The results showed that none of the cases studied had concomitant gene amplification. These results suggest that other post-transcriptional mechanisms might be responsible for cyclin D-1 protein over-expression in benign apocrine lesions. Further studies are needed to understand the mechanisms involved in abnormal cyclin D-1 expression in these lesions.

Topics: Apocrine Glands; Chromosomes, Human, Pair 11; Cyclin D1; Female; Fibrocystic Breast Disease; Gene Amplification; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Metaplasia; Up-Regulation

To examine the histopathological features of 24 surgically resected carcinoma in situ (CIS) involving sclerosing adenosis (SA), with special reference to the topographical relationship between CIS and SA.. In 13 (54%) lesions, CIS was entirely surrounded by SA (type A) and in 11 (46%), CIS involved SA at least focally but was not confined to the SA area (type B). The mean size of CIS in type B (30.45 mm) was significantly larger than in type A (18.00 mm). The mean size of SA in type A (39.46 mm) was significantly larger than in type B (19.54 mm). Most type A CIS were non-high-grade, and the oestrogen receptor (ER)(+)/progesterone receptor (PgR)(+)/HER2(-) immunophenotype predominated. Most type B CIS were high-grade and six (54%) were ER(-)/PgR(-). Most type A were bcl-2(+)/p53(-) in both SA and CIS areas, but two (18%) apocrine ductal CIS of type B were bcl-2(-)/p53(+) in both SA and CIS areas. Expression of ER and cyclin D1 in SA was not different from that of SA unassociated with cancer.. Most CIS involving SA arises within SA and high-grade DCIS tends to grow beyond SA. Occasional CIS may arise outside SA and secondarily involve SA.

Topics: Adult; Aged; Breast Neoplasms; Calcium-Binding Proteins; Calponins; Carcinoma in Situ; Carcinoma, Intraductal, Noninfiltrating; Comorbidity; Cyclin D1; Female; Fibrocystic Breast Disease; Humans; Membrane Proteins; Microfilament Proteins; Middle Aged; Proto-Oncogene Proteins c-bcl-2; Receptor, ErbB-2; Receptors, Estrogen; Receptors, Progesterone; Retrospective Studies; Sclerosis; Tumor Suppressor Protein p53

Centrosome amplification (CA) contributes to carcinogenesis by generating aneuploidy. Elevated frequencies of CA in most benign breast lesions and primary tumors suggest a causative role for CA in breast cancers. Clearly, identifying which and how altered signal transduction pathways contribute to CA is crucial to breast cancer control. Although a causative and cooperative role for c-Myc and Ras in mammary tumorigenesis is well documented, their ability to generate CA during mammary tumor initiation remains unexplored. To answer that question, K-Ras(G12D) and c-Myc were induced in mouse mammary glands. Although CA was observed in mammary tumors initiated by c-Myc or K-Ras(G12D), it was detected only in premalignant mammary lesions expressing K-Ras(G12D). CA, both in vivo and in vitro, was associated with increased expression of the centrosome-regulatory proteins, cyclin D1 and Nek2. Abolishing the expression of cyclin D1, Cdk4 or Nek2 in MCF10A human mammary epithelial cells expressing H-Ras(G12V) abrogated Ras-induced CA, whereas silencing cyclin E1 or B2 had no effect. Thus, we conclude that CA precedes mammary tumorigenesis, and interfering with centrosome-regulatory targets suppresses CA.

Topics: Animals; Apoptosis; Cell Proliferation; Cell Transformation, Neoplastic; Cells, Cultured; Centrosome; Cyclin D1; Cyclin-Dependent Kinase 4; Epithelial Cells; Female; Fibrocystic Breast Disease; Genes, ras; Humans; Mammary Glands, Animal; Mice; Mice, Transgenic; NIMA-Related Kinases; Protein Serine-Threonine Kinases; Signal Transduction

Caveolin-1 is the principal structural component of caveolae microdomains, which represent a subcompartment of the plasma membrane. Several independent lines of evidence support the notion that caveolin-1 functions as a suppressor of cell transformation. For example, the human CAV-1 gene maps to a suspected tumor suppressor locus (D7S522/7q31.1) that is frequently deleted in a number of carcinomas, including breast cancers. In addition, up to 16% of human breast cancers harbor a dominant-negative mutation, P132L, in the CAV-1 gene. Despite these genetic associations, the tumor suppressor role of caveolin-1 still remains controversial. To directly assess the in vivo transformation suppressor activity of the caveolin-1 gene, we interbred Cav-1 (-/-) null mice with tumor-prone transgenic mice (MMTV-PyMT) that normally develop multifocal dysplastic lesions throughout the entire mammary tree. Herein, we show that loss of caveolin-1 gene expression dramatically accelerates the development of these multifocal dysplastic mammary lesions. At 3 wk of age, loss of caveolin-1 resulted in an approximately twofold increase in the number of lesions (foci per gland; 3.3 +/- 1.0 vs. 7.0 +/- 1.2) and an approximately five- to sixfold increase in the total area occupied by these lesions. Similar results were obtained at 4 wk of age. However, complete loss of caveolin-1 was required to accelerate the appearance of these dysplastic mammary lesions, because Cav-1 (+/-) heterozygous mice did not show any increases in foci development. We also show that loss of caveolin-1 increases the extent and the histological grade of these mammary lesions and facilitates the development of papillary projections in the mammary ducts. Finally, we demonstrate that cyclin D1 expression levels are dramatically elevated in Cav-1 (-/-) null mammary lesions, consistent with the accelerated appearance and growth of these dysplastic foci. This is the first in vivo demonstration that caveolin-1 can function as a transformation suppressor gene.

Topics: Age Factors; Animals; Antigens, Polyomavirus Transforming; Breast Neoplasms; Caveolin 1; Caveolins; Cell Transformation, Neoplastic; Cyclin D1; DNA-Binding Proteins; Female; Fibrocystic Breast Disease; Gene Expression Regulation; Humans; Male; Mammary Glands, Animal; Mice; Mice, Transgenic; Milk Proteins; Mitogen-Activated Protein Kinases; STAT5 Transcription Factor; Trans-Activators

Breast cysts are associated with an increased risk of breast cancer. Some biomarkers such as estrogen receptor alpha (ERa), progesterone receptor (PR), and cyclin D1, show similar patterns of expression in epithelial cells lining breast cysts as malignant epithelial cells in local and invasive ductal breast cancer. We have attempted to answer two questions: (1) Do epithelial cells lining breast microcysts (cysts which can only be seen with a microscope) express biomarkers in a similar pattern to breast ductal carcinoma in situ and invasive ductal carcinoma? (2) Are breast microcysts precursors of breast cancer or are they part of normal involution of the breast? Seventy two archival open breast biopsy specimens of ductal carcinoma in situ and invasive ductal carcinoma and 32 normal breast biopsies from Australian women who had breast reduction surgery were selected from hospital archives. All specimens were analysed by standard immunohistochemistry for ERa, PR, cyclin D1, bcl-2, p53 and erbB-2 expression. In the same specimens, the pattern of high biomarker expression was very similar for all the above biomarkers in epithelial cells lining microcysts and in both ductal carcinoma in situ and invasive ductal carcinoma c. ErbB-2 was not expressed in normal control specimens. ErbB-2 was expressed in the same specimens in an increasing proportion of normal breast acini, microcysts and cancer cells in 36% of specimens with breast cancer. An apparent progression was observed from normal breast acini, to proliferation of epithelial cells in microcysts, ductal carcinoma in situ and invasive ductal carcinoma in the same specimen. When these findings are considered with other reports we conclude: (1) that epithelial cells lining breast cysts highly express biomarkers in a similar pattern to ductal carcinoma in situ and invasive ductal carcinoma; (2) that some microcysts are not part of normal involution of the breast and in some women may be part of the transition from normal to cancer.

Topics: Biomarkers, Tumor; Biopsy; Breast; Breast Neoplasms; Carcinoma, Intraductal, Noninfiltrating; Cyclin D1; Estrogen Receptor alpha; Female; Fibrocystic Breast Disease; Humans; Immunoenzyme Techniques; Middle Aged; Proto-Oncogene Proteins c-bcl-2; Receptor, ErbB-2; Receptors, Estrogen; Receptors, Progesterone; Tumor Suppressor Protein p53

Topics: Breast Neoplasms; Carcinogenicity Tests; Carcinoma, Ductal, Breast; Carcinoma, Intraductal, Noninfiltrating; Cyclin D1; Cyclins; Female; Fibrocystic Breast Disease; Gene Expression Regulation; Humans; Oncogene Proteins; Oncogenes; RNA, Messenger

The elucidation of molecular alterations that occur during human breast cancer progression may contribute to the development of preventative strategies. Using in situ hybridizations on a cohort of 94 biopsy lesions, quantitatively increased cyclin D mRNA expression levels were observed in only 18% of benign lesions, which confer no or slightly increased breast cancer risk, and 18% of premalignant atypical ductal hyperplasias, which confer a four to fivefold increase in breast cancer risk. The transition to carcinoma was accompanied by frequent cyclin D mRNA overexpression in 76% of low-grade ductal carcinomas in situ, 87% of higher grade comedo ductal carcinomas in situ and 83% of infiltrating ductal breast carcinomas. The data identify a molecular event that may separate benign and premalignant human breast lesions from any form of breast carcinoma.

Topics: Breast Neoplasms; Carcinoma, Ductal, Breast; Carcinoma, Intraductal, Noninfiltrating; Cohort Studies; Cyclin D1; Cyclins; Female; Fibrocystic Breast Disease; Gene Expression; Humans; Neoplasm Invasiveness; Oncogene Proteins; Precancerous Conditions; RNA, Messenger

Patients with benign breast biopsies that exhibit atypical epithelial proliferation or fibroadenoma may be at increased risk for invasive breast cancer. We hypothesized that molecular markers might also be useful to evaluate the malignant potential of nonneoplastic breast tissue.. Study subjects belonged to a cohort of 6,805 women who underwent biopsy for nonmalignant breast disease at the Mayo Clinic and Rochester-affiliated hospitals between 1967 and 1981. As part of a nested case-control study that compared subjects who developed invasive breast cancer with those who did not, we analyzed a sample of 60 benign breast biopsies for the following markers: HER-2/neu and p53 over-expression by immunohistochemistry, HER-2/neu and PRAD-1 amplification using differential polymerase chain reaction (PCR), and p53 mutation using single-strand conformation analysis (SSCA) and direct DNA sequencing by asymmetric PCR.. None of 60 biopsies showed amplification of HER-2/neu or PRAD-1. Five samples exhibited low-level immunoreactivity to the HER-2/neu protein product. Fourteen samples exhibited focal or diffuse immunoreactivity to the p53 protein. Point mutations in the p53 gene were found in five samples: three of these samples exhibited mutations that altered the amino acid sequence. Only two of five samples with p53 mutation exhibited p53 overexpression. Histologic diagnoses on three samples with nonconservative p53 mutation were, respectively, nonproliferative fibrocystic change, papillomatous hyperplasia, and fibroadenoma.. The clinical significance of p53 mutation, p53 overexpression, and low-level HER-2/neu expression in benign breast tissue remains to be determined. Further research will be necessary to evaluate whether these markers could serve as useful adjuncts to histology in evaluation of the malignant potential of benign breast tissue.

Topics: Base Sequence; Biopsy; Breast Diseases; Breast Neoplasms; Case-Control Studies; Cyclin D1; Cyclins; DNA Mutational Analysis; Female; Fibroadenoma; Fibrocystic Breast Disease; Gene Amplification; Genes, p53; Humans; Hyperplasia; Immunohistochemistry; Molecular Sequence Data; Oncogene Proteins; Point Mutation; Polymerase Chain Reaction; Polymorphism, Single-Stranded Conformational; Receptor, ErbB-2; Tumor Suppressor Protein p53