The Function and Oncological Significance of PD-L1 and its Antibodies

Abstract

The PD-L1 protein, also known as programmed death-ligand 1 is a protein encoded in the CD274 gene. Specifically, PD-L1 belongs to the immunoglobulin superfamily of proteins, and it is a transmembrane protein that allows nutrients across the cell membrane 11. PD-L1 works in close connection with T cells (thymus cells) and B cells (bone marrow or bursa-derived cells)1. PD-L1 binds to the PD-L receptor on T cells to regulate and sometimes inhibit (in the case of cancer) the activated T cells, B cells, and myeloid cells. Once their activation is inhibited by PD-L1, the T-cells are unable to fight foreign substances in the body like infections, diseases, and cancers, thus allowing cancerous tumors to grow without check3. Elevated levels of PD-L1 have been found in a variety of cancers, including melanoma, non-small cell lung cancer (NSCLC), Hodgkin’s lymphoma, bladder cancer, renal cell carcinoma (RCC), head and neck squamous cell carcinoma (HNSCC), breast cancer, Merkel cell carcinoma, hepatocellular carcinoma (HCC) and gastric cancer (GC)4. Among other information, this study also examines the protein sequence of PD-L1, alignments of the sequence, the structure, functional domains, gene expression, copy number, and mutation profiles.