Neoadjuvant Chemotherapy in Triple Negative Breast Cancer: Correlation between Androgen Receptor Expression and Pathological Response

Background: There is growing evidence that the response to chemotherapy may be affected by Androgen Receptor (AR) expression suggesting that triple-negative breast cancers (TNBC) AR+ and quadruple negative breast cancer (QNBC) subtypes may have different diseases behavior. Methodology: We retrospectively estimated the predictive value of the AR expression in stage II and stage III TNBC patients treated with neoadjuvant chemotherapy (NAC) and correlated with the rate of pathological response (pCR). Results: Of 89 TNBC patients, 29 patients (32.6%) were TNBC AR+ and 60 patients (67.4) were QNBC. Most of the patients were less than 60 years old. Of note, approximately 62% in the QNBC group were less than 40 years old compared with 39 % in the TNBC AR+ group. The Ki-67 expression was higher in the QNBC in comparison with TNBC AR+ being 86.7% and 65.5%, respectively. QNBC subgroup showed higher rates of pCR compared with TNBC; 60% and 24%, respectively. Higher Ki-67 expression, higher grade, and lymph node involvement were statistically significantly correlated with the rate of pCR in the QNBC group (p=0.02, p=0.04, and p=0.03, respectively). In contrast, no significant association was observed between pCR and clinical-pathological features in the TNBC AR+ group. Conclusion: Our results suggested that the AR expression in TNBC may be applied as a predictive marker for NAC. TNBC AR+ had a lower rate of pCR compared with QNBC, suggesting that this subtype may have a partial chemoresistance.