How to induce ovarian cancer: and how not to.

It has been hypothesized that pregnancy and oral contraceptives (OCs) exert a protective effect on the risk of ovarian cancer through the suppression of ovulation. Even short periods of OC use have been associated with about a 40% reduction in the incidence of ovarian cancer. There has also been renewed interest in the role of gonadotropins in producing ovarian cancer. However ovarian cancer plateaus after menopause at which time there are sustained high concentrations of gonadotropins. Cyclic gonadotropins have an essential role in the monthly production of steroids and research in this area is expected to increase understanding of how ovulation seems to affect the incidence of ovarian cancer. Although 1 study suggesting that pregnancy has a permanent effect on the pituitary secretion of trophic hormones was based on tenuous anatomical grounds some semipermanent resetting of a homeostatic control mechanism does appear to be involved. The differences in the backgrounds of ovarian and breast cancer are thought to be attributable to differing hormone sensitivities in the tissues involved.