FCGR3A (Fc Fragment Of IgG Receptor IIIa): FCGR3A, also known as CD16a, is a receptor that binds to the Fc region of immunoglobulin G (IgG). It is expressed on natural killer cells, macrophages, and certain T cells, where it mediates antibody-dependent cellular cytotoxicity (ADCC) and assists in clearing pathogens and antibody-coated cells. Variations in FCGR3A can affect the risk of autoimmune diseases and responses to cancer immunotherapy.