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 8 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
