USP21 and hepatocellular carcinoma: Deneddylation enzymes consist of ATXN3, COPS5 (also known as CSN5 or JAB1), SENP8 (also known as NEDP1 or DEN1), UCHL1, UCHL3, and USP21 in humans.8 Using qRT‐PCR, we detected the expression of these deneddylation enzymes in 40 pairs of HCC and ANL tissues.