Nature Cancer, Published online: 13 March 2026; doi:10.1038/s43018-026-01137-yRNA N6-methyladenosine (m6A) is the most abundant internal RNA modification, yet its functional landscape in cancer remains poorly defined. A study now introduces a METTL3-based RNA base-editing screen that maps functional m6A sites and reveals m6A-dependent translational activation of the tumor suppressor CHD9 in prostate cancer and beyond.