For instance, circMTO1 act as a sponge of miR-9 and suppressed HCC cell proliferative ability and thus positively regulated p21, a cell cycle inhibitory protein; hsa_circ_100338 promoted HCC cell migratory and invasive abilities through directly regulating miR-141; ciRS-7 facilitated HCC cell proliferative and invasive abilities by targeting hsa-miR-7-5p (miR-7) and thus upregulating CCNE1, EGFR and PIK3CD [30, 35–38]. Here, PIK3CD is linked to hepatocellular carcinoma.