In plasmacytoid dendritic cells in vitro and in vivo (in tumor-draining lymph nodes), indoximod was found to downregulate IDO1 expression and function, decrease kynurenine production and increase T cell proliferation, while promoting a phenotypic shift in T cells from Treg to Th17-producing T helper cells (80). This evidence concerns the gene IDO1 and neoplasm.