To obtain direct evidence of the role of macrophages for in vivo killing, we found that the use of a neutralizing mAb against the chemokine (C-C motif) ligand 2 (CCL2) resulted in a selective depletion of CD11b+F4/80+ cells within the tumor (Figure 3G), and abrogated immunoprotection in TCR-Tg mice (Figure 3H). This evidence concerns the gene CCL2 and neoplasm.