Ly6G (Lymphocyte antigen 6 complex, locus G6D) is a 21-25 kD glycosylphosphatidylinositol (GPI)-anchored protein and a member of the Ly-6 superfamily, predominantly expressed on myeloid-derived cells such as neutrophils, granulocytes, and monocytes. It serves as a key marker for identifying and distinguishing these cell populations, especially neutrophils, due to its tightly regulated expression during cell differentiation and maturation. In addition to its role as a cell surface marker, Ly6G is involved in cell signaling and adhesion processes. It has also been implicated in various immunological studies, including antitumor responses and the modulation of immune cell functions in both normal and pathological conditions.