In contrast, type II NKT dominant tumor models, such as subcutaneous 15-12RM fibrosarcoma and CT26-L5 colon carcinoma, grow normally in Jα18 KO mice but do not grow at all in CD1d KO mice, highlighting the requirement of suppressive type II NKT cells in promoting tumor progression of these cells. This evidence concerns the gene CD1D and fibrosarcoma.