Thus, there was higher expression of melanoma-specific genes in lungs of Mcpt4/Mcpt6/CPA3-deficient vs. wild type mice, and mice with a Mcpt4/Mcpt6/Cpa3-deficiency also exhibited reduced numbers of cells expressing CD1d, an MHC class 1-like molecule important for presenting antigen to invariant NKT (iNKT) cells. Here, CD1D is linked to melanoma.