PD-L1

PD-L1 is a protein expressed on the surface of various cells, including immune and tumor cells, where it plays a crucial role in regulating immune tolerance. It interacts with the PD-1 receptor on T cells, an interaction essential for maintaining immune homeostasis by inhibiting excessive immune activation. Normally, PD-L1 helps prevent autoimmunity by reducing immune responses against self-antigens. However, changes in PD-L1 expression, such as overexpression in tumor cells, can lead to immune evasion by tumors, allowing cancer cells to avoid detection and destruction by the immune system. In research and clinical settings, PD-L1 is a significant biomarker and therapeutic target, especially in oncology. Its expression levels are often analyzed using immunohistochemistry to guide cancer treatment decisions, particularly in the context of immunotherapies like PD-1/PD-L1 inhibitors. These therapies aim to block the PD-L1/PD-1 interaction, thereby enhancing T cell activity against tumors. Understanding PD-L1's role in immune regulation provides insights into both tumor biology and potential therapeutic interventions, making it a focal point in the development of new cancer treatments.