CircRNA HIPK3 (circHIPK3, circRNA ID: hsa_circ_0000284), composed of the second exon (1099nt) of the HIPK3 gene [5], promotes tumor metastasis and enhances the proliferation and invasion of cancer cells in HCC by acting as a sponge for miRNA [6, , -9]. Here, HIPK3 is linked to hepatocellular carcinoma.