Background:
Breast cancer is the most common cancer in females. It is the main cause of cancer-related deaths in women. Despite the benefit of using standard treatment modalities like chemotherapy, anti-Her-2 monoclonal antibodies, and hormonal therapy in the prognosis of breast cancer, 15% of breast cancer patients will have metastases and die. Grand effort has been given to understand breast cancer oncogenesis which helped with the approval of several drugs targeting cancer cells like immune therapy. The immune system has a significant role in the behavior of cancer. Contemporary, immunotherapy development through the immune checkpoint blockers demonstrated promising antitumor effects in multiple cancers that don't respond to conventional treatments. Despite promising results, a good response is seen only in part of patients, and there is still a need for a monotherapy modality with curative ability.
Conclusion:
PD-1/L1 pathway aids the development and progression of cancer. It promotes cancer by negatively regulating the immune responses mediated by T-cells and inhibiting proliferation, migration, and effector function of T cells. PD-1/L1 blockade treatment showed a promising effect in cancer immunotherapy. This type of immunotherapy is significantly effective in malignancies containing a high expression of PDL-1/2.