HDAC9 and hepatocellular carcinoma: Xie et al. 65proved that the elevated expression of has_circ_0078710 promoted cell proliferation, migration and tumour growth in hepatocellular carcinoma (HCC), which acts as a ceRNA for miR‐31 to increase HDAC and CDK2 expression and regulate expression of other cell cycle components, including CDK4, cyclin D1, cyclin A and p21.