In light of the previously mentioned role of human RNASET2 in modulating the macrophage activation/polarization state, to further investigate the oncosuppressive role of T2 Ribonucleases in the context of a completely immunocompetent experimental model we report here the in vivo role of the murine Rnaset2 gene by overexpressing it in either mammary adenocarcinoma-derived TS/A or C51 colon carcinoma murine cells and injecting them subcutaneously in syngeneic BALB/c mice, using both empty vector-transfected (E) and parental (P) cells as a control. The gene discussed is RNASET2; the disease is colon carcinoma.