Considering the fact that IDO1 overexpression in melanoma cells upregulates Tregs and impairs the function of CD8+ and CD4+ T cells63, EPA has an impact role on activation of human tumor antigen-specific cytotoxic T cell line, proliferation of CD8+ T and NK cells, production of IFN-γ, and supression of Tregs10. This evidence concerns the gene IDO1 and neoplasm.