THBS1 and neoplasm: Together these results suggest that TGFβ signaling is tumor suppressive at early stages via its growth inhibition of carcinogen-initiated epithelial cells; but as tumor cells become resistant to TGFβ’s growth inhibitory effects, TGFβ produced by the tumor or other cells acts on the stroma to enhance malignant progression via induction of VEGF, MMPs and down-regulation of thrombospondin-1.