Predictive Role of Molecular Subtypes in Response to Neoadjuvant Chemotherapy in Breast Cancer Patients

Abstract

Background: Breast cancer is increasingly regarded as a heterogeneous disease which can be classified into distinct molecular subtypes with prognostic significance. Objectives: Retrospective evaluation of the response to neoadjuvant chemotherapy for patients with the major molecular subtypes of breast cancer as classified using immunohistochemical assay and to investigate the patterns of benefit from the neoadjuvant chemotherapy in different molecular subtypes Materials and methods: ER, PR, HER2 and ki-67 were used to divide102 breast cancer patients treated with neoadjuvant chemotherapy (NCT) into 4 subtypes: luminal A (ER+,PR+,HER2-, and ki-67 ≤14%), luminal B (ER+, PR+,HER2-and ki-67>14% ; ER+ and/or PR+, HER2+), HER2-overexpression (ER-, PR-and HER2+) and triple-negative (ER-, PR-,and HER2-). Results: Of the 102 patients analyzed, 9 patients (8.8% of all patients) achieved pCR with 2.6% (2/76) for luminal subgroup, 0.0% (0/8) for HER2-overpression subgroup and 38.9% (7/18) for triple-negative subgroup with a high statistical significant value (p=0.000). Conclusions: Molecular subtypes are good predictors for response to NCT in breast cancer patients. Compared to luminal A tumors, HER2-overexpression and triple-negative subtypes are more sensitive to NCT.