To date, five HDAC inhibitors (HDACi)—vorinostat(SAHA), belinostat, chidamide, romidepsin, and panobinostat (Figure S1a)—have been approved to treathematological malignancies.12 The potentialof belinostat as an anti-HCC agent has been studied in a clinicaltrial (NCT00321594).13 The trial resultsrevealed that patients on belinostat treatment had median progression-freesurvival (PFS) and overall survival (OS) of 2.64 and 6.60 months,respectively.13 While this result supportsthe potential of HDACi for HCC treatment, enhancing their efficacyremains a key challenge. Here, HDAC9 is linked to hepatocellular carcinoma.