In KIRC, <i>ALDH1L2</i> silencing increased ROS levels and reduced Akt/mTOR/S6K phosphorylation, consistent with decreased EdU incorporation.<h4>Conclusion</h4>This study is the first to systematically untangle the divergent roles of <i>ALDH1L2</i> in KIRC, BLCA, and PRAD from a pan-cancer perspective combined with ex vivo experiments, suggesting that <i>ALDH1L2</i> may serve as an important molecule influencing tumor progression and the immune microenvironment, thereby providing a new potential target for the diagnosis and treatment of related cancers. The gene discussed is AKT1; the disease is cancer.