The inhibins are a family of growth factors comprised of several different species that are secreted in the female principally from the ovarian follicle. The inhibins perform best as markers of ovarian cancer when measured collectively (total inhibin) by immunoassays targeted to common epitopes. After menopause with the depletion of ovarian follicles, the circulating level of total inhibin becomes undetectable. In contrast, serum total inhibin levels are elevated in women with ovarian cancer, in particular those with granulosa cell tumours and those with the mucinous subtype of epithelial carcinoma. Investigations into the clinical utility of inhibin to detect ovarian cancer have shown that it complements CA125, an established marker of epithelial ovarian cancer, in that each performs best in detecting different subtypes of ovarian cancer. In some published studies, the two markers together have detected up to 95% of ovarian cancers with 95% specificity.