Immune response induced by preoperative chemotherapy in breast cancer: Role of peripheral natural killer (pNK) cell activity, tumor-infiltrating lymphocytes (TILs), and tumor microenvironment factors (TMEFs).

e12644Background: TILs are predictive and prognostic factors in HER2 type and triple negative breast cancer patients undergoing neoadjuvant chemotherapy. NK cells exert innate immunity, a decrease in NK cells is associated with an increased risk of breast cancer recurrence. TMEFs affect tumor immune surveillance. Relationships between immune response and therapeutic effect induced by preoperative chemotherapy were assessed by pNK cell activity, TILs, and TMEFs. Methods: 28 patients with stage II-IV breast cancer underwent preoperative chemotherapy with nab-PTX/FEC, nab-PTX/FEC/trastuzumab (Tz), DTX/FEC, FEC/nab-PTX, FEC/nab-PTX/Tz, FEC/DTX, or FEC/DTX/Tz. pNK cell activity, TILs, and TMEFs were assessed before and after chemotherapy. TILs were evaluated by H&E staining of biopsy samples and surgical specimens, and TMEFs were assessed by NGS for CD4, CD8, NK, FOXP3, CTLA-4, PD-1, PD-L1, IL-2, IL-6, IL-12, IFN-γ, IL-10, TGF-β, and VEGF using the FFPE samples. Results: Pathologic therapeutic effects were: Gr...