ADD3 and hepatocellular carcinoma: Circ-ADD3 inhibits HCC metastasis by enhancing the interaction between CDK1 (Cyclin Dependent Kinase 1) and the oncoprotein EZH2 (Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit), resulting in EZH2 ubiquitination and degradation in HCC (41).