PD-1/PD-L1 pathway: Current research in breast cancer.

INTRODUCTION: Immunotherapy has shown encouraging outcomes in breast cancer (BC) treatment in recent years. The programmed cell death ligand 1 (PD-L1) transmembrane protein is suggested to function as a co-inhibitory factor in the immune response, where it collaborates with programmed cell death protein 1 (PD-1) to stimulate apoptosis, suppress cytokine release from PD-1 positive cells, and limit the growth of PD-1 positive cells. Furthermore, in many malignancies, PD-L1 reduces the immune system's response to neoplastic cells. These observations suggest that the PD-1/PD-L1 axis plays a vital role in cancer therapy and the regulation of cancer immune escape mechanisms. This review aimed to provide an overview of the functions of PD-1 and PD-L1 in BC cancer therapy. METHODS: This research design is a literature review. The style is a traditional review on topics or variables relating to the PD-1/PD-L1 pathway. A literature search was carried out using three online databases. RESULTS: The search using the keywords yielded a total of 248 studies. Each result was filtered again according to the inclusion and exclusion criteria, resulting in a final total of 4 studies to be included in the literature review. CONCLUSIONS: The combination of PD-1/PD-L1 is essential for many malignancies. According to the evidence presented, this combination presents both an opportunity and a challenge in cancer treatment. Since many solid cancers, especially BC, express high levels of PD-1/PD-L1, cancer treatment mainly involves targeted therapies.

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.