SMURF2 and nonpapillary renal cell carcinoma: Notably, TGFβ signaling was negatively correlated to ubiquitination signaling (Figure 5A), and Fukasawa et al. (2010) showed that the ubiquitination degradation process of TGFβ-RII mediated by Smurf2 was significantly enhanced in renal cell cancer, which might be the reason for the TGFβ signaling attenuation in ccRCC.