N7-methylguanosine-related MiRNAs Predict Hepatocellular Carcinoma Prognosis and Immune Therapy

N7-methylguanosine (mG) modification has been notably linked with the development of many tumors. However, no investigations have been conducted on whether mG-related miRNA (mG-miRNA) is a prognostic index of hepatocellular carcinoma (HCC). Therefore, this investigation aimed to establish a predictive mG-miRNA signature for efficient HCC prognosis and elucidate the associated immune cell infiltration (ICI) and functions in the tumor microenvironment. RNA sequencing and clinical data on 375 HCC and 50 healthy tissue samples were acquired from The Cancer Genome Atlas database. The mG-miRNA regulators methyltransferase-like 1 and WD repeat domain 4 were acquired from the TargetScan database. Univariate Cox regression analysis was conducted on the 63 differentially expressed mG-miRNAs identified. A prognostic signature that consisted of seven miRNAs was identified. According to their risk scores, individuals with HCC were divided into high-risk (HR) and low-risk (LR) cohorts. A Kaplan-Meier test revealed that survival in the HR HCC patients was poorer than in the LR cohort (p < 0.001). The area under the receiver operating characteristic curves of 1-, 3-, and 5-year overall survival were 0.706, 0.695, and 0.715, respectively. A nomogram of sex, risk score, age, and stage indicated the HCC patients' overall survival. Furthermore, it was indicated that the HR and LR patients had different degrees of ICI and immune function. A pathway enrichment analysis revealed the association of several immunity-linked pathways with the risk model. In conclusion, the signature established has great prognostic value and could be used as a new immunotherapy target for individuals with HCC.