Interestingly, 1,25-(OH)2D3 upregulates PD-L1 in human (but not mouse)-cultured epithelial and immune cells [294], while vitamin D treatment increases PD-1 expression in CD24+CD25+int T-cells in Crohn’s disease patients [295] and PD-L1 in epithelial and immune cells in melanoma patients [296]. Here, CD274 is linked to melanoma.