Although no significant difference was observed between circ_MAPK9 and gender, age, pathological grade, tumor size, TNM stage and other clinicopathologic characteristics (Supplementary Table 4), Kaplan–Meier and log-rank test analyses suggested that the higher circ_MAPK9 expression in patients with HCC was negatively correlated with overall survival (OS) and disease-free survival (DFS) of HCC patients (P = 0.0016 for OS, P < 0.001 for DFS; Fig. 3E-F). This evidence concerns the gene MAPK9 and hepatocellular carcinoma.