Selective genome editing of amplified oncogenes triggers immunogenic cell death and tumor remodeling.

Oncogene amplifications fuel some of the most lethal, therapy‑refractory cancers, yet remain clinically untargeted. We report a single‑guide CRISPR/Cas9 strategy that converts the sheer copy‑number excess of oncogene amplicons into an Achilles' heel. A solitary intronic double‑strand break is innocuous in diploid genomes but collapses oncogene amplification‑positive cells across neuroblastoma, small‑cell lung and colorectal carcinoma models, driving > 90% loss of viability, G₂/M blockade and catastrophic DNA‑damage signalling. Amplified‑locus cleavage rewires transcription toward cell death activation, necroptosis and cGAS-STING-mediated immunogenic cell death, enabling dendritic‑cell cross‑priming and T‑cell activation and proliferation. In xenografts, delivery of the intronic sgRNA shrinks tumours by 90%, prolongs survival and remodels the innate tumour microenvironment. Deep sequencing confirms negligible off‑target editing, and combination with doxorubicin achieves supra‑additive killing. These findings establish amplification density, not sequence content, as a tractable, tumour‑exclusive target and unveil a dual‑action platform that is simultaneously cytotoxic and immunostimulatory. Editing of tumor amplifications therefore offers a blueprint for translating copy‑number aberrations into precision genome‑editing therapies for treatment‑resistant cancers.