Objective: The role that Beclin 1 (BECN1) plays in the development and progression of cancer mediated by autophagy, as well as its differential expression in breast cancer cell lines and mammary tumor tissue according to the molecular subtype, has been demonstrated. The objective of this study was to evaluate the association of BECN1 cytoplasmic expression with clinical and pathologic response, recurrence, disease-free survival (DFS) and overall survival (OS) in patients with locally advanced breast cancer (LABC), according to immunophenotype.
Patients and methods: 64 patients with non-triple negative LABC and 20 patients with triple negative LABC who received preoperative chemotherapy were included in an observational, analytical and retrospective study to evaluate the cytoplasmic expression of BECN1 protein by immunohistochemistry in microarrays of breast cancer tissue obtained before treatment. Association between BECN1 and clinicopathological characteristics, clinical and pathologic response to preoperative chemotherapy and recurrence, were analyzed using Chi-square or Fisher's exact test. Postoperative DFS and OS were assessed by Kaplan-Meir curves, and the difference according to BECN1 expression was evaluated using the log-rank test. The bivariate analysis was performed using the Cox Proportional Hazards Model. A p-value of < 0.05 was considered statistically significant.
Results: BECN1 staining revealed positive expression in 62.5% of patients with non-triple negative and 60.0% with triple negative LABC. No association was observed between BECN1 expression and clinical or pathological response or recurrence. An association of the BECN1 expression with lower OS in triple negative breast cancer was found (HR = 5.19; 95% CI 1.12-24.02; p = 0.035).
Conclusions: Results showed an association of the cytoplasmic expression of BECN1 with a lower OS, which could be a poor prognostic biomarker in triple negative LABC.