COL1A1 and cancer: These findings are consistent with our results that vactosertib decreases ECM proteins such as α-SMA, COL1A1, and FIBRONECTIN, including PAI-1, which are increased in radiation-induced fibrous tissue by inhibition of TGF-β signaling, therefore, these results supported the therapeutic potential of vactosertib in the reduction of the risk of radiotherapy-induced fibrosis in cancer patients.