KDM5A and hepatocellular carcinoma: H3K4me3, a marker of active gene expression, is the substrate of lysine demethylase 5A (KDM5A).15, 16 KDM5A, an oncogene and a promising drug target, has been reported to contribute to tumorigenesis, metastasis and drug resistance by repressing gene expression through demethylating H3K4me3.17, 18, 19 Moreover, a previous study has implied KDM5A being significantly up‐regulated in HCC.20