Remarkably, in a number of neoplasms, high SKI and/or SnoN protein levels in tumor cells are observed, concomitant with (a), elevated levels of secreted TGF-β and (b), a great sensitivity of tumor cells to targeted inhibition of TGF-β signaling that strongly interferes with their tumorigenic and metastatic potential. This evidence concerns the gene TGFB1 and neoplasm.