METTL3 and hepatocellular carcinoma: METTL3 mediates the expression of m6A to promote the formation of circRNA HPS5 (circHPS5), which can act as a miRNA 370 (miR-370) sponge to regulate the expression of high-mobility group AT-hook 2 (HMGA2) and further accelerate tumorigenesis in HCC cells, providing a potential prognostic marker and therapeutic target (Rong et al., 2021b).