Variant prostate carcinoma and elevated serum CA-125

Introduction: About 10% of tumors derived from nongynecologic, noncoelomic tissues react with the OC125 antibody. Some patients with advanced prostate cancer were found to have elevated serum CA-125 level. Materials and methods: We examined the clinical history of 11 patients with castration resistant prostate cancer and an elevated serum CA-125 level. Pathological review and immunohistochemical staining were performed on tumors from eight of these patients. Results: Patients with advanced prostate cancer and an elevated serum CA-125 level responded to androgen ablative therapy (median duration, 27 months). They were predisposed to develop persistent or recurrent urinary symptoms and visceral metastases. Eight of 11 patients had a low or undetectable serum prostate-specific antigen level (= 4 ng/mL) or an elevated serum carcinoembryonic antigen level (> 6 ng/mL). In 3 of 7 patients whose specimens were available for further review, the tumors contained histologic features compatible with a diagnosis of ductal or endometrioid adenocarcinoma of the prostate. Conclusions: Patients with prostate cancer and an elevated serum CA-125 level have unique clinical and pathologic characteristics. Some of these patients possess tumors compatible with a subtype of prostate cancer known as ductal adenocarcinoma. Additional studies need to be performed to elucidate the biologic basis of the various subtypes of prostate cancer.