MDM4 and colorectal cancer: Considering that MDM2 and MDMX are highly expressed in prostate, breast, cervical, and colorectal cancer (Cressey et al., 2006; Voruganti et al., 2015; Qin et al., 2016a, b, 2017; Stiasny et al., 2017; Wang et al., 2018a), USP7-mediated stabilization of MDM2 and MDMX may also contribute to the progression of these diseases.