ABSTRACT
Objective:To analyze the predictive value of tumor-infiltrating lymphocyte (TIL) fraction in patients with breast cancer treat-ed with neoadjuvant chemotherapy. Methods: Clinicopathological data of 156 female patients with breast cancer diagnosed using core needle biopsy and treated with neoadjuvant chemotherapy and surgery between November 2015 and April 2017 in Tianjin Medi-cal Uninvertity Cancer Institute and Hospital were retrospectively analyzed. Patients were assigned into 3 groups based on the TIL frac-tim, namely high, intermediate and low TIL fractin gronp. The response to neoadjuvant chemotherapy was evaluated using the histo-pathological criteria for assessment of therapeutic response in breast cancer. The relation between TIL fraction and response to neoad-juvant chemotherapy was then analyzed. Results:Neoadjuvant chemotherapy was effective in 78.2%(122/156) of the patients. Pa-tients harboring tumors with a higher TIL fraction were more likely to achieve a better response to neoadjuvant chemotherapy than those harboring tumors with a lower TIL fraction (P<0.01). Patients harboring hormonal receptor (HR)-negative tumors generally exhib-ited a higher TIL fraction than those harboring HR-positive tumors (P<0.01). The TIL fraction, but not HR status, human epidermal growth factor receptor 2 (HER-2) status, or Ki-67 index, correlated with response to neoadjuvant chemotherapy. Conclusion:TIL frac-tion is an independent predictive factor of response to neoadjuvant chemotherapy in patients with breast cancer. Patients with breast cancer exhibiting higher TIL fraction achieve better response to neoadjuvant chemotherapy than those exhibiting lower TIL fraction.