Androgen receptor expression inversely correlates with histological grade and N stage in ER.sup.+/PgR.sup.low male breast cancer

Purpose Androgen Receptor (AR) positivity is often displayed in breast cancer and especially in Male Breast Cancer (MBC), where it appears to be a heterogeneous feature, with its expression ranging between 38 and 81% of cases. Given the fact that circulating androgens represent the most important sex hormones in males and that breast carcinogenesis is characteristically subjected to hormonal mechanisms, our purpose was to investigate the clinicopathological significance of AR in MBC assessing if its expression could be associated with parameters of tumor aggressiveness. Methods Clinical and pathological data were retrospectively reviewed for male patients with a diagnosis of invasive breast cancer. AR status was detected by immunohistochemistry on formalin-fixed, paraffin-embedded tumoral tissue sections. Correlations between AR expression and histopathological features were assessed using univariate and multiple comparisons where appropriate, assuming P values < 0.05 as statistically significant. Results The study included 44 consecutive male patients. AR expression ranged between 10 and 98% and the majority of cases presented a moderate to high expression of this receptor. Adopting a 20% PgR cut-off, statistical analyses highlighted a different behavior of AR: in ER.sup.+/PgR.sup.high group, it positively correlated with the other steroid receptors pointing out the importance of hormonal cross-talk: in ER.sup.+/PgR.sup.low group, AR status inversely correlated with histological grade and lymph node status. Conclusion Hormonal factors reveal to play a crucial role in MBC carcinogenesis and progression. Intriguingly, in ER.sup.+/PgR.sup.low tumors AR expression significantly correlates with lymph node status, hinting at a favorable biological role of AR in this tumor subgroup.