Ly6G, or lymphocyte antigen 6 complex locus G6D, is a cell surface marker predominantly expressed on neutrophils and granulocytes in mice. It is a GPI-anchored protein that plays a role in cell signaling and cell adhesion, and is often used as a marker for these particular cell populations. The expression of Ly6G directly correlates with the level of differentiation and maturation of these cells. In the context of immune cell research, Ly6G is often used alongside Ly6C, another cell surface marker that, together with Ly6G, helps distinguish between different granulocyte subsets. The Ly6G protein can also be targeted for therapeutic purposes. The depletion of Ly6G+ cells has been shown to affect tumor growth in certain cancer models, suggesting that neutrophils may have a role in promoting tumor progression in some contexts.