AROMATASE AND STEROID-RECEPTORS IN GYNECOMASTIA AND MALE BREAST-CARCINOMA - AN IMMUNOHISTOCHEMICAL STUDY

Hormonal factors have been implicated in the development of male breas t disorders, including carcinoma and gynecomastia. We studied the expr ession of aromatase and estrogen (ER), progesterone (PR), and androgen (AR) receptors by immunohistochemistry in male breast carcinoma (15 c ases) and gynecomastia (30 cases) to evaluate their possible significa nce in these disorders. Relatively strong aromatase immunoreactivity w as observed in all cases of carcinoma, but in only 11 of 30 cases (37% ) of gynecomastia. ER and PR expression was observed in the nuclei of ductal cells in all the cases of gynecomastia. More than 10% ofthe car cinoma cells were positive for ER and PR in 9 of 15 (60%) and 10 of 15 (67%) carcinomas, respectively. AR immunoreactivity was observed in n uclei of both epithelial and non-epithelial cells. AR was present in d uctal or carcinoma cells in 13 of 15 (87%) cases of carcinoma and in a ll 30 (100%) cases of gynecomastia. The mean percentages of ER-, PR-, and AR-positive cells were significantly higher in gynecomastia than i n carcinoma. There was a close association of AR with ER (P <0.01) and PR (P <0.01) in cases of gynecomastia, but there was a significant in verse correlation between AR and ER (P <0.01) or PR (P <0.05) expressi on in carcinoma cases. Increased aromatase expression in the stromal c ells is considered to contribute to the increment in the in situ estro gen concentration and the development of male breast carcinoma.