Inhibitory circRNAs include hsa_circ_0007059, which inactivates Wnt/β-catenin and ERK1/2 pathways due to inhibition of microRNA-378 leading to lung cancer suppression [48], circRNA C3P1 that inhibits HCC growth and metastasis through modulating miR-4641/PCK1 axis [49], circRNA MTO1 that up-regulates p21 expression and inhibits HCC invasion through sponging oncogenic miR-9 [50], and circRNA TRIM33-12 that also suppresses HCC through the inhibitory effect on miRNA-191 [51]. Here, MTO1 is linked to hepatocellular carcinoma.