USP21 and hepatocellular carcinoma: We found that COPS5 (adjusted P‐value = 2.37E−40, fold change = 1.806), UCHL1 (adjusted P‐value = 3.15E−07, fold change = 1.509), and USP21 (adjusted P‐value = 1.25E−29, fold change = 1.511) were also upregulated in HCC in this microarray data (Table S10).