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.
Keywords: Programmed death ligand-one; breast cancer; grading; histopathological results; immunohistochemistry; metastasis.