ELEVATED SERUM INHIBIN CONCENTRATIONS IN POSTMENOPAUSAL WOMEN WITH OVARIAN-TUMORS

Background. Inhibin is an ovarian hormone that inhibits the secretion of follicle-stimulating hormone (FSH) by the anterior pituitary gland. Women with granulosa-cell tumors of the ovary have elevated serum inh ibin concentrations, but whether the concentrations are increased in w omen with other ovarian tumors is unknown. Methods. We measured serum inhibin and FSH concentrations before surgery in 212 postmenopausal wo men with suspected ovarian cancer and after surgery in 210 of them. Re sults. Eighteen of the 22 women (82 percent) with mucinous carcinomas (mucinous cystadenocarcinomas and mucinous borderline cystic tumors) o f the ovary had elevated serum inhibin concentrations, whereas only 9 of the 53 women (17 percent) with serous carcinomas (serous cystadenoc arcinomas and serous borderline cystic tumors) had elevated levels. Se rum inhibin concentrations were also elevated in 2 of 12 women (17 per cent) with clear-cell carcinomas, 4 of 26 women (15 percent) with undi fferentiated carcinomas, 3 of 3 women (100 percent) with granulosa-cel l tumors, and 5 of 27 women (19 percent) with other ovarian cancers. T he serum concentrations of inhibin were increased in 2 of 28 women (7 percent) with nonovarian pelvic cancers and 11 of 41 women (27 percent ) with benign ovarian diseases. All women but one with initially eleva ted serum inhibin concentrations had low values one week after surgery . Serum inhibin concentrations correlated negatively with serum FSH co ncentrations (P = 0.05) in women with granulosa-cell tumors but not in women with other tumors, suggesting that the inhibin secreted by tumo rs in the latter group has decreased biologic activity. Conclusions. S erum inhibin concentrations are elevated in most postmenopausal women with mucinous carcinomas of the ovary and in some women with other typ es of epithelial ovarian tumors. The concentrations fall after tumor r emoval.