Expression of androgen receptor in breast cancer & its correlation with other steroid receptors & growth factors

BACKGROUND & OBJECTIVES: Breast cancer is the second most common malignancy in Indian women. Among the members of the steroid receptor superfamily the role of estrogen and progesterone receptors (ER and PR) is well established in breast cancer in predicting the prognosis and management of therapy, however, little is known about the clinical significance of androgen receptor (AR) in breast carcinogenesis. The present study was aimed to evaluate the expression of AR in breast cancer and to elucidate its clinical significance by correlating it with clinicopathological parameters, other steroid receptors (ER and PR) and growth factors receptors (EGFR and CD105). METHODS: Expression of AR, ER, PR, epidermal growth factor receptor (EGFR) and endoglin (CD105) was studied in 100 cases of breast cancer by immunohistochemistry (IHC). Risk ratio (RR) along with 95% confidence interval (CI) was estimated to assess the strength of association between the markers and clinicopathological characteristics. Categorical principal component analysis (CATPCA) was applied to obtain new sets of linearly combined expression, for their further evaluation with clinicopathological characteristics (n=100). RESULTS: In 31 cases presenting with locally advanced breast cancer (LABC), the expression of AR, ER, PR, EGFR and CD105 was associated with response to neoadjuvant chemotherapy (NACT). The results indicated the association of AR+ (P=0.001) and AR+/EGFR- (P=0.001) with the therapeutic response to NACT in LABC patients. The AR expression exhibited maximum sensitivity, specificity and likelihood ratio of positive and negative test. The present results showed the benefit of adding AR, EGFR and CD105 to the existing panel of markers to be able to predict response to therapy. INTERPRETATION & CONCLUSIONS: More studies on the expression profiles of AR+, AR+/CD105+ and AR+/EGFR- in larger set of breast cancer patients may possibly help in confirming their predictive role for therapeutic response in LABC patients.