PTGDR and hepatocellular carcinoma: The subcellular fractionation assay and the RNA fluorescent in situ hybridization showed that KDM4A-AS1 was predominantly localized in the cytoplasm rather than in the nucleus of HCC cells (Fig. 4A and Supplementary Fig. 5), inspiring us that KDM4A-AS1 might function as a ceRNA to sequester specific miRNAs and enhance target gene expression.