In addition, circMTO1 can inhibit the progression of HCC by promoting the expression of P21 by acting as a sponge for miR‐9, suggesting that circMTO1 can be a potential target for HCC treatment.45 CircZKSCAN1, derived from the zinc finger family gene ZKSCAN1, was found to be crucially downregulated in HCC tissues compared with non‐tumorous tissues.46 Further study showed that decreasing the expression of circZKSCAN1 promoted the proliferation, invasion, and distant metastasis of HCC cells.46 This study indicates that circZKSCAN1 may serve as a potential diagnostic biomarker for HCC. The gene discussed is ZKSCAN1; the disease is hepatocellular carcinoma.