Prognostic significance of EGFR, MUC1 and PD-L1 expressions in cases with triple negative breast cancer

Purpose: Twenty percent of the breast cancers are triple negative (TNBC). Despite the impressive progression in the biology of this subgroup, data is limited as compared to hormone and/or HER2 positive cases. Thus, the aim of this study was to detect the expression levels and to identify the prognostic values of MUC1, EGFR and PD-L1 in TNBC. Methods: MUC1, EGFR and PD-L1 expressions were detected by immunohistochemistry in 97 cases with TNBC. Associations between clinical and histopathological parameters with overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method and compared by the log-rank test. Prognostic effects were analyzed by Cox proportional hazard models. Results: During a median follow-up of 93 months (0.6-168.7) the mean PFS was 110.1 and OS was 121.8 months. Tumor diameter (T), involved lymph node status (N) and TNM stage were found to be prognostic for PFS and OS. PD-L1 in microenvironment (PD-L1 ME) and EGFR expression were found to be associated with longer PFS and OS, but MUCI and tumor PD-L1 (PD-L1 TM) expressions were not. All combined analyses showed that in the subgroups of MUC1, PD-L1 TM or ME positive, EGFR expression was correlated with longer PFS and OS than those who were not. Older age (>= 70 years), T and N status and also EGFR expression were found to be independent prognostic factors for OS in Cox regression analysis. Conclusion: EGFR expression was found to be one of the most important prognostic factors in addition to T and N status in cases with TNBC.