CDK5 and liver cancer: In our previous study, we showed that the lncATG9B-4 promote the proliferation and migration of liver cancer cells and positively regulated the expression of cyclin-dependent kinase 5 (CDK5) in the liver cancer cells.[10] According to the mechanism by which lncRNAs negatively regulate target genes, it could be inferred that lncATG9B-4 indirectly regulates the expression of CDK5.