SKP2 and colorectal carcinoma: Our results showed a trend that Skp2 is required to maintain Mcl-1 stability in IR-treated CRC cells, and depletion of Skp2 increased Mcl-1 ubiquitination (Fig. 4C), and Skp2 is positively correlated with Mcl-1 expression in CRC tissues (Fig. 7H), suggesting Skp2 plays a role in maintaining of Mcl-1 stability and expression upregulation, finally contributes to tumorigenesis of CRC.