Steroid receptors and response of ovarian cancer to hormones in vitro.

Oestrogen receptor (ER) and progesterone receptor (PR) content and the response in vitro to tamoxifen (T), medroxyprogesterone acetate (MPA) and to a combination of the two hormones were determined in 21 epithelial ovarian carcinomas. The response was assessed by the level of adenosinetriphosphate in the cells. ER and PR were detected in 62% and 57%, respectively, with significant variations between the different histopathological cancer types. ER and PR predicted the response in vitro in 62% of the tumours exposed to the combined hormones, and in 38% and 33% of those exposed to T and MPA, respectively. The value of steroid-receptor determinations in selecting the proper hormonal treatment in ovarian cancer is significantly reduced because of the high proportion of incorrect predictions.