USP7 and cancer: In particular, p53 transcriptional activity is often disrupted in HCC by highly expressed HAUSP; moreover, the expression of nuclear PTEN decreases in patients with advanced‐stage HCC.5, 7, 17, 18 Thus, HCC forms an appropriate model for our study; indeed, it has been known that HCC is one of the 10 most common cancer types worldwide with no ideal treatment.17