Background <p>Recently, prostate cancer (PCa) has been increasing in incidence and mortality, which seriously threatens men’s physical and mental health. Adenosine (A)-to-inosine (I) RNA editing, contributing to nearly 90% of all editing events in human, has been reported to contribute to pathogenesis and progression of cancer. Here, we aimed to elaborate the role and mechanism of A-to-I-edited POLA2 in PCa.</p> Methods <p>RT-qPCR, Western blotting, and immunohistochemistry were used to assess gene expression. RNA editing levels were determined by Sanger sequencing. Colony formation, CCK-8, and Transwell assays were conducted to detect cell proliferation and metastasis. And Flow cytometry assay was applied to examine CD8+ T cell activity and tumor cell apoptosis. Dual-luciferase reporter assay demonstrated the relationship between gene and miRNA. The ability of glycolysis was measured by Seahorse XF96 Analyzer.</p> Results <p>A-to-I RNA overediting of POLA2 was identified in PCa patients, which was related to unfavorable clinical outcomes and prognosis. The A-to-I RNA editing of POLA2 was mediated by ADAR1 enzyme in human cancers. Functionally, A-to-I RNA editing endowed POLA2 with carcinogenicity in PCa development, and POLA2 overediting aggravated cell viability and metastasis of PCa. More importantly, POLA2 overediting fortified glycolysis and impaired CD8+ T cell cytotoxicity in PCa. Mechanically, edited POLA2 upregulates BTBD7 expression in PCa by binding to miR-596.</p> Conclusion <p>A-to-I RNA edited POLA2 attained carcinogenesis in PCa by impeding immune infiltration, fortifying glycolysis and upregulating BTBD7, indicating that edited POLA2 has the potential to become a tool for gene therapy.</p>