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

Introduction: Breast cancer is increasingly regarded as a heterogeneous disease which can be classified into distinct molecular subtypes with prognostic significance. Materials and methods: ER, PR, HER2 and ki-67 were used to divided 102 breast cancers treated with neoadjuvant chemotherapy (NCT) into 4 subtypes: luminal A (ER+, PR+, HER2-, and ki-67 ${\leq}14%$), 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: Among 102 patients, a pCR was seen in 16 (15.7%) patients. The pathologic complete remission (pC) rates according to different subtypes are as follows: luminal A, 0 of 20 (0.0%), luminal B, 2 of 23 (8.7%), HER2-overexpressio,n 4 of 18 (22.2%), and triple-negative, 10 of 41 (24.4%) (p=0.041). In triple-negative subtype patients, the rates of pCR differed significantly among the 3 chemotherapy regimens with 5.6% (1/18) for CEF (cyclophosphamide, epirubicin and flurouracil), 20.0% (1/5) for TE (docetaxel and epirubicin) and 44.4% (8/18) for TCb (docetaxel and carboplatin) (p=0.024). In locally advanced breast cancer patients, the rates of pCR seem to differ among the 3 chemotherapy regimens with 6.7% (2/30) for CEF, 0.0% (0/8) for TE and 23.1% (6/26) for TCb, but this did not attain statistical significance (p>0.05). Conclusions: Molecular subtypes are good predictors for response to NCT in breast cancer patients in Northeast China. Compared with luminal A tumors, HER2-overexpression and triple-negative subtypes are more sensitive to NCT. For triple-negative breast cancer, we concluded that the TCb combination is a promising NCT regimen. Our results also indicated that the TCb combination is promising for the treatment of locally advanced breast cancer.