Abstract:

Objective The purpose of this study was to detect the expression of programmed death-ligand 1(PD-L1) in triple negative breast cancer, and to explore the relationship between the expression of PD-L1 and the clinicopathological features and prognosis of triple negative breast cancer. Method From May 2010 to October 2020, 269 paraffin sections of triple negative breast cancer tissue collected by Beijing Chaoyang Hospital Affiliated to Capital Medical University, were used for immunohistochemical staining to detect the expression of PD-L1 in breast cancer tissue. Analyze the relationship between PD-L1 positive expression and clinical pathological characteristics and prognosis of patients. Result The expression rate of PD-L1 in tumor cells and infiltrating

lymphocytes around tumor was 7.8%（21/269） and 17.84%（48/269）. The total expression rate of PD-L1 in tumor cells and infiltrating lymphocytes around tumor was 21.19%（57/269）.The total expression of PD-L1 in tumor and peritumor infiltrating lymphocytes was correlated with histological grade, nerve invasion, vascular tumor emboli, lymph node metastasis, and Ki-67 high proliferation index. Multivariate regression analysis showed that lymph node metastasis was risk factor for the expression of PD-L1. The expression of PD-L1 was associated with RFS in the prognosis of triple negative breast cancer. Conclusion The high expression of PD-L1 in the tumor cells of triple negative breast cancer and the infiltrating lymphocytes around the tumor is related to the tumor progression and poor prognosis, which can be used as the target of triple negative breast cancer immunotherapy.

Key words: Programmed death-ligand 1, Triple negative breast cancer, Immunohistochemistry, Clinicopathological characteristics, Prognosis