calcitriol and Testicular-Neoplasms

Seminomas have been rarely associated with malignant hypercalcemia. The responsible mechanism of hypercalcemia in this setting has been described to be secondary to 1,25-dihydroxyvitamin D secretion. The relationship with PTHrP has not been determined or studied.The aim of this study is to describe and discuss the case and the pathophysiological mechanisms involved in a malignant hypercalcemia mediated by 1,25-dihydroxyvitamin D and PTHrP cosecretion in a patient with seminoma.. A 35-year-old man was consulted for assessment and management of severe hypercalcemia related to an abdominal mass. Nausea, polyuria, polydipsia, lethargy and confusion led him to the emergency department. An abdominal and pelvic enhanced CT confirmed a calcified pelvic mass, along with multiple retroperitoneal lymphadenopathy. Chest x-ray revealed "cannon ball" pulmonary metastases. The histopathology result was consistent with a seminoma. Serum calcium was 14.7 mg/dl, PTH was undetectable, 25-dihydroxyvitamin D was within normal values and PTHrP and 1,25-dihydroxyvitamin were elevated (35.0 pg/ml, and 212 pg/ml, respectively). After the first cycle of chemotherapy with bleomycin, etoposide and cisplatin, normocalcemia was restored. Both PTHrP and 1,25-dihydroxyvitamin D, dropped dramatically to 9.0 pg/ml and 8.0 pg/ml, respectively.. The association of seminoma and malignant hypercalcemia is extremely rare. We describe a case of a patient with a seminoma and malignant hypercalcemia related to paraneoplastic cosecretion of 1,25-dihydroxyvitamin D and PTHrP. After successful chemotherapy, calcium, PTHrP and 1,25-Dihydroxyvitamin D returned to normal values.

Topics: Adult; Humans; Hypercalcemia; Lung Neoplasms; Male; Paraneoplastic Syndromes; Parathyroid Hormone; Parathyroid Hormone-Related Protein; Prognosis; Seminoma; Testicular Neoplasms; Vitamin D

Testicular germ cell tumours (TGCTs) are the most common malignancy in young men aged 18-35 years. They are clinically and histologically subdivided into seminomas and non-seminomas. 1,25-Dihydroxyvitamin D (1,25(OH)(2)D(3)) is the active form of vitamin D and exerts its actions via a specific intracellular vitamin D receptor (VDR). Several investigations in the recent years have revealed, in addition to a physiological occurrence of the VDR in various tissues, VDR expression in different human malignancies. Furthermore, 1,25(OH)(2)D(3) plays an important role in the regulation of cell proliferation and differentiation. In different normal and malignant cell types, antiproliferative and pro-differentiating effects of 1,25(OH)(2)D(3) are described. We investigated whether TGCT express the VDR, wether differences exist between the histological subtypes and if vitamin D has a function on the proliferation of tumour cells. Furthermore, we investigated the potential function of the vitamin D-regulated genes nuclear receptor co-repressor 1(NCOR1), nuclear receptor co-repressor 2 (NCOR2), thyroid receptor interacting protein 15 (TRIP15), Growth Arrest and DNA Damage (GADD45), MAP kinase-activated protein kinase 2 (MAPKAPK2), Cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) and Cytochrome P450, family 27, subfamily B, polypeptide 1 (CYP27B1) in the pathogenesis of TGCT. We demonstrate, for the first time, that primary TGCT as well as TGCT cell lines, express VDR mRNA and protein. Vitamin D and VDR may play a role in the pathogenesis of TGCTs. Furthermore, vitamin D inhibits proliferation of TGCT cell-lines, potentially via an increase in expression of GADD45. Our data suggest that vitamin D could play a role in antitumour therapy.

Topics: Adult; Biomarkers, Tumor; Blotting, Western; Cell Proliferation; Humans; Immunoenzyme Techniques; Male; Neoplasms, Germ Cell and Embryonal; Real-Time Polymerase Chain Reaction; Receptors, Calcitriol; RNA, Messenger; Signal Transduction; Testicular Neoplasms; Vitamin D