Abstract
Introduction: Neoadjuvant treatment in locally advanced breast cancer (LABC) is intended to decrease the cancer mass, increase the likelihood of radical resection and improve survival. Resistance to chemotherapy may depend on cellular expression of anti-apoptotic proteins. XIAP and survivin are the most potent inhibitors of apoptosis (IAP), but their role in drug-induced cancer cell apoptosis remains unclear. This study was designed to evaluate the impact of pre-treatment expression of XIAP and survivin on pathological complete response and survival in LABC patients. Material and methods: The study included 60 LABC patients treated with anthracycline-based chemotherapy. XIAP and survivin expression was assessed immunohistochemically in pre-treatment core biopsy specimens. Results: Pathological complete response was achieved in 33% of the LABC patients. Low/intermediate expression of both XIAP and survivin was significantly associated with pathological complete response (p ≤ 0.04 and p < 0.001, respectively) and positively correlated with disease-free survival (p = 0.017 and p < 0.001) and overall survival (p = 0.052 and p < 0.001). The area under receiver operating characteristics curves (AUC) revealed predictive value of survivin expression for relapse and death in breast cancer patients (AUC = 0.63, p = 0.001 and AUC = 0.8, p < 0.001, respectively). Conclusions: Our findings suggest that downregulation of XIAP and survivin in LABC patients might predict better treatment outcomes after anthracycline-based chemotherapy. This, in turn, may indicate XIAP and survivin proteins as potential targets for innovative anticancer therapies.