Subsequently, they showed that circRNA_100284, delivered by exosomes to normal liver cells, could up-regulate the expression of Enhancer Of Zeste Homolog2 (EZH2) which is a potential marker for proliferation and cyclin-D1 which regulates the G1 to S phase transition in the cell cycle by acting as a sponge for miR-217, thus accelerating the cell cycle, promoting cell proliferation and malignant transformation of untransformed cells in hepatocellular carcinoma (HCC). This evidence concerns the gene CCND1 and hepatocellular carcinoma.