The expression of programmed death-ligand 1 and its association with histopathological grade, stage of disease, and occurrence of metastasis in breast cancer.

INTRODUCTION Programmed death ligand 1 (PD-L1) plays a role in tumor escape and progression by inactivating T lymphocytes. The aim of the study reported here was to determine the relationship between the expression of PD-L1 and histopathological grade, stage of disease, and the occurrence of metastasis in breast cancer. METHODS The observational cross-sectional study involved analyzing the expression of PD-L1 by immunohistochemistry. RESULTS PD-LI was expressed in 43 of 60 patients with breast cancer (71.6%), mostly with a moderate histopathological grade (58.3%) and at an advanced stage (50%). Associations between the expression of PD-L1 and histopathological grade (p = 0.011), stage of disease (p = 0.009), and the occurrence of metastasis (p = 0.01) were significant, with an odds ratio of 5. CONCLUSION The associations between the expression of PD-L1 and histopathological grade, disease stage, and occurrence of metastasis were all significant in cases of breast cancer in the sample. Those findings suggest that the expression of PD-L1 increases the progression of breast cancer.