Changes of immunohistochemical biomarkers before and after neoadjuvant chemotherapy in breast cancer and their prognosis

Objective: To investigate changes in the expression of immunohistochemical (IHC) markers and factors associated with the effect of chemotherapy before and after neoadjuvant chemotherapy (NAC). Methods: A retrospective study included 200 breast cancer patients treated with NAC between January 2016 and December 2018. We analyzed the changes in the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and Ki-67 in pre- and post-treated samples and the predictive factors of NAC. Results: Among the 200 cases, 16 cases were luminal A, 108 cases were luminal B, 36 cases were HER2+subtype, and 40 cases were basal-like. Twenty-five patients (12.50%) achieved pathological complete remission (PCR).There were significant differences in PR and Ki-67 before and after NAC but there were no differences in ER and HER2.In univariate analysis, factors associated with PCR were tumor less than 5 cm(P=0.009), non-luminal breast cancer (P=0.001), ER negative(P=0.001), PR negative (P=0.029) and HER2 positive(P=0.001). Tumor less than 5 cm [P=0.020, OR=2.581, 95%CI (1.207, 5.753)], ER negative [P=0.011, OR=2.264, 95%CI (1.207, 4.248)] and HER2 positive[P=0.007, OR=2.412, 95%CI (1.275, 4.561)] remained predictive variables in multivariate analysis after correction for the other variables. Conclusions: The expression of Ki-67 decreases after NAC. Negative PR and ER and positive HER2 status are related to the efficacy of pCR for breast cancer, and have guiding significance for the prognosis evaluation of NAC.