Nuclear androgen receptor as marker of responsiveness to medroxyprogesterone acetate in human renal cell carcinoma

The presence of steroid receptors in human renal cell carcinoma (RCC) has been reported by many authors. However some controversy exists regarding the response of human RCC to medroxyprogesterone acetate (MPA). The hypothesis that the MPA effect on tumor growth might be due to the androgenic action of the progestin was suggested since 1976. Based on the recent report that in mouse kidney the androgenic action of progestins correlates with nuclear uptake but not with cytosol androgen receptor (AR c), 24 human RCC were studied for the presence of AR c and 14 for the presence of AR c and nuclear androgen receptor (AR n) in order to establish a parameter more suitable to define the tumor responsiveness to MPA. Tritiated methyltrienolone (R1881) plus cold triamcinolone acetonide and R1881 was employed with the dextran-coated charcoal method. AR c was detected in 19 out of 38 (50%) and AR n in 8 out of 14 (57%) of the tumors examined. Therefore androgen receptors not only help to define, with estrogen and progesterone receptors, the hormone-dependent human RCC, but may also be useful in the selection of patients to be treated with MPA. In fact, the androgenic activity of MPA could counteract the promoting action of estrogens on tumor growth only in the patients with AR n positive tumor.