Proliferative activity and steroid hormone receptor status in male breast carcinoma.

Hormonal factors have been implicated in the development of both female and male breast cancers (MBC). However, MBCs are rare and seem to have different biological behavior than those of females. The aim of this study was to evaluate proliferative activity and to establish an association with steroid hormone receptor concentration and clinicopathological parameters in MBC. Proliferative activity was assessed in 18 MBC by mitotic figure counts and immunohistochemical evaluation of MIB-1 and proliferating cell nuclear antigen (PCNA). Estrogen (ER), progesterone (PR) and androgen (AR) receptors were evaluated in serial section from the same tumor by immunohistochemistry. PCNA (range 17-73%; mean, 51.6%) and MIB-1 (range 18.5-58%; mean 38.4%) were positive correlated with the mitotic rate. High proliferative activity assessed either by mitotic index or MIB-1 expression was associated with more poorly differentiated tumors. Sixty one percent (11/18) of the tumors were ER+, 72% (13/18) PR+ and 38.5% (5/13) AR+. Proliferative activity in tumors displaying ER+/PR+ phenotype showed a tendency to be higher than in ER-/PR- tumors. This difference was statistically significant when MIB-1 expression was used as proliferation marker. An association between AR concentration and age at diagnosis was found; in the AR negative group (8/13) mean age at diagnosis was 54.4 +/- 7.3 which was significantly lower than the age of patients with AR+ tumors, 63.2 +/- 11.1 (5/13). Results presented here show that decreased androgen action (AR-) within the breast might contribute to an earlier development of MBC. Besides that, the presence of ER and PR in carcinoma cells is considered to provide a growth advantage as shown by the positive association between the phenotype (ER+/PR+) and high proliferative activity. These results add information for a better understanding of hormonal control of MBC growth and development.