The control of tumor growth was again significantly impaired in mice that had received an Env immunization compared with unvaccinated mice (Figure 5A), and it was significantly improved when Env-immunized mice were treated with an anti-IL-10 antibody (Figures 5B, C), proving the mechanistic role of IL-10 also in the suppression of FBL-3 tumor control. This evidence concerns the gene ERVW-1 and neoplasm.