IDO1 and melanoma: Therefore, a possible scenario in melanoma, DC, and IDO1 interaction may be as follows: inflammatory cytokines produced by innate immunity in response to melanoma may modulate CD83 and IDO1 expression on LCs and generate CD83+ LCs, either IDO1+/− which migrated to SLN (real mature SLN LCs and regulatory/inhibitory SLN LCs).