In samples from E0771-GFP tumor-bearing CCR2−/− mice where ranitidine has previously been shown to not inhibit tumor growth (11), overall, IgG1 and IgG2a antibody production was decreased compared with wild-type C57BL/6 mice and ranitidine treatment was associated with an increase in GFP-specific IgG2a, albeit not significant (Figure 1). This evidence concerns the gene CCR2 and neoplasm.