N7-甲基鸟苷 (m7G) 修饰与许多肿瘤的发展密切相关。然而，目前尚未研究m7G相关miRNA（m7G-miRNA）是否是肝细胞癌（HCC）的预后指标。因此，本研究旨在建立预测性 m7G-miRNA 特征，以实现有效的 HCC 预后，并阐明肿瘤微环境中相关的免疫细胞浸润 (ICI) 和功能。从癌症基因组图谱数据库中获取了 375 个 HCC 和 50 个健康组织样本的 RNA 测序和临床数据。 m7G-miRNA 调节子甲基转移酶样 1 和 WD 重复结构域 4 是从 TargetScan 数据库获取的。对鉴定出的 63 个差异表达 m7G-miRNA 进行单变量 Cox 回归分析。鉴定出由 7 个 miRNA 组成的预后特征。根据风险评分，HCC 患者被分为高风险 (HR) 和低风险 (LR) 队列。 Kaplan-Meier 检验显示，HR HCC 患者的生存率低于 LR 队列 (p < 0.001)。 1年、3年和5年总生存率的受试者工作特征曲线下面积分别为0.706、0.695和0.715。性别、风险评分、年龄和分期列线图表明了 HCC 患者的总体生存率。此外，还表明HR和LR患者存在不同程度的ICI和免疫功能。通路富集分析揭示了几种免疫相关通路与风险模型的关联。总之，所建立的特征具有很大的预后价值，可以作为 HCC 个体的新免疫治疗靶点。

N7-methylguanosine (m7G) modification has been notably linked with the development of many tumors. However, no investigations have been conducted on whether m7G-related miRNA (m7G-miRNA) is a prognostic index of hepatocellular carcinoma (HCC). Therefore, this investigation aimed to establish a predictive m7G-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 m7G-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 m7G-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.