Murine Trem2 mRNA was detected in wild-type mice, while human TREM2 mRNA was detected in homozygous B-hTREM2 mice by RT-PCR. TREM2 protein was detected in microglia and tumor-derived macrophages isolated from wild-type and homozygous B-hTREM2 mice by flow cytometry. Human TREM2 protein was detected in B-hTREM2 mice by western blot using an anti-human TREM2 antibody. Anti-human TREM2 antibody (analog) was effective in controlling MC38 and EMT-6 tumor growth in B-hTREM2 mice.