On the one hand, TGF-β facilitates an alteration in differentiation into the Treg phenotype, while IL-23 and IL-6 maintain the Th17 phenotype; on the other hand, in the case of a deficiency of TGF-β, IL-23 and IL-12 induce the conversion of Th17 cells to a Th1 cell phenotype [72,73]. The molecular pathways of PGE2 released by breast tumor cells in increasing IL-23 production and Th17 cell proliferation are highlighted in the study [74]. This evidence concerns the gene TGFB1 and breast neoplasm.