Abstract A20: Analysis of tumor infiltrating lymphocytes and expression of PD1 and PD-L1 in breast tumors prior to and after neoadjuvant chemotherapy

Introduction: The effect of chemotherapy on the presence of tumor-infiltrating lymphocytes (TILs) and expression of PD1 and PD-L1 is unclear. We sought to describe the differences in the percentage (%) of TILs, cytotoxic T lymphocytes (CTL), and expression of PD1/PD-L1 in tumors of patients (pts) with operable breast cancer (BC) treated with neoadjuvant chemotherapy (NAC) who were enrolled in a biomarker study at our institution (IRB protocol#...