After coculture of CD11b+ cells isolated from a tumor-challenged mice with OVA-specific CD8+ T cells, FcγRIIB-competent CD8+ T cells were selectively driven to apoptosis by WT but not Fgl2–/– CD11b+ cells, a phenomenon that we did not observe in Fcgr2b–/– OVA-specific CD8+ T cells. This evidence concerns the gene FCGR2B and neoplasm.