We further showed that treatment with the SIRPγ mAb significantly increased phagocytosis in the in vivo tumor model, as assessed by 2 distinct methods: (a) quantification of F4/80+CD11b+ macrophages containing GFP, indicative of having engulfed labeled A549 cells; and (b) the ratio of human-specific sequences (derived from tumor cells) to mouse-specific sequences in DNA extracted from macrophages isolated by flow cytometry from the tumor-bearing mice (Figure 10, E–G). Here, SIRPG is linked to neoplasm.