TGFB1 and cancer: It is worth noting that Myc can induce miR-17/92 cluster which targets key proteins in TGFβ signal transduction and represses gene regulation downstream of TGFβ in multiple cancer cell lines, and that the pro-tumorigenic property of Myc overexpression is lost in TGFβ-deficient xenograft models of colorectal cancer; such evidence suggests that Myc may promote tumor growth primarily by repressing the anti-tumorigenic gene expression (including TSP-1) activated by TGFβ signaling, at least in the context of colorectal cancer [141, 142].