Abstract
BACKGROUND: Increasing studies have demonstrated the biological function of RNA N6-methyladenosine (m6A) modifications in tumorigenesis. However, the potential role of m6A modifications in the tumor immune microenvironment (TIME) of hepatocellular carcinoma (HCC) remains unclear. METHODS: Herein, 23 m6A regulators were fetched and introduced into consensus clustering to identify distinct m6A modification patterns and develop m6A-based molecular signatures. Then, a principal component analysis algorithm was employed to construct an m6A-based scoring system to further quantify m6A modification patterns in individual tumors. Immunophenoscore (IPS) was used to estimate the immunotherapeutic response of patients. RESULTS: Three different m6A modification patterns with distinct prognoses and biological signatures were identified among 611 HCC samples. The TIME characteristics of these three patterns were consistent with three known immune profiles: immune-oasis, immune-excluded, and immune-inflamed phenotypes. Identifying m6A modification patterns within individual tumors based on the m6Ascore, developed under the m6A-related signature genes, contributed to elaborating biological processes, clinical outcomes, immune cell infiltration, immunotherapeutic effects, and genetic variations. The low-m6Ascore subtype, characterized by immunosuppression, suggested an immune-suppressed phenotype and a low probability of benefiting from immunotherapy. Finally, the potential function of PRDM4 in HCC was explored. CONCLUSION: This study comprehensively elucidated the indispensable role of m6A modification patterns in the complexity of TIME. The quantitative identification of m6A modification patterns in individual tumors will contribute to optimizing precision immunotherapy.