PRMT9 and hepatocellular carcinoma: Our previous study showed that PRMT9 is highly expressed in HCC and closely associated with patient survival, and the up-regulation of PRMT9 in HCC is closely related to hepatitis B virus antigen [12], suggesting that high PRMT9 expression in HCC may be associated with HBV infection and that PRMT9 expression may be regulated by the HBx protein.