SMAD3 and cancer: Current reported studies show that TRIP13 can regulate several cancer-related factors, including TGF-β1, SMAD3, NOTCH and DNA-PKcs complex proteins.18,32,33 Our study showed that TRIP13 knockdown decreased the protein expression of c-MYC and its downstream molecules, CDK4 and CCND1, and the expression of P21 was increased in TRIP13-knockdown GBM cells.