Therefore, F9H4 + cetuximab inhibit tumor growth in immunocompetent mice that express human Fcγ receptors, and this activity requires endogenous NK cells and macrophages for optimal efficacy and is associated with higher expression levels of surface CD16a in blood NK cells but downregulation of CD16a in intratumoral NK cells and macrophages. The gene discussed is FCGR3A; the disease is neoplasm.