Abstract 4109: Pan-cancer landscape of IDH1/2 mutations with a focus on non-small cell lung cancer: Insights from the AACR GENIE Registry

Abstract Background: IDH1 and IDH2 mutations are oncogenic drivers across several tumor types. Their prevalence, mutational spectrum, and co-alteration profiles in Non-Small Cell Lung Cancer (NSCLC) remain incompletely defined. Given the availability of approved IDH1 and IDH2 inhibitors, characterizing these mutations has potential therapeutic relevance. Methods: We queried the AACR GENIE v18 database (n=250, 018 tumor samples) to assess IDH1/2 mutation frequency, subtype distribution, associated histologies, co-mutations and survival outcomes in NSCLC. Results: IDH1 and IDH2 mutations were identified in 5, 380 (2. 2%) and 2, 761 (1. 1%) patients, respectively. IDH1 mutations—primarily R132H (50. 4%) and R132C (20. 6%) —were enriched in gliomas (42. 6%), cholangiocarcinoma (6. 0%), lung adenocarcinoma (4. 8%), and melanoma (4. 4%). IDH2 mutations—mainly R140Q (20%) and R172K (9. 8%) —were most frequent in AML (20. 3%), colorectal cancer (7. 4%), and NSCLC (5. 9%). Among 30, 454 NSCLC patients, IDH1 and IDH2 mutations occurred in 1. 2% and 0. 7%, respectively. EGFR co-mutations were found in 83 (21. 8%) of IDH1- and 39 (22%) of IDH2-mutant NSCLC. KRAS co-mutations were seen in 170 (44. 5%) of IDH1- and 51 (29%) of IDH2-mutant NSCLC (Table). Across major oncogenic subgroups, IDH co-mutations occurred in 1. 04% (IDH1) and 0. 60% (IDH2) of EGFR L858R, 1. 18% and 0. 13% of EGFR E746A750del, and in 2. 01% and 0. 81% of KRAS G12C, respectively. Among 1, 846 patients with available survival data, the median overall survival (OS) was 14. 7 months for stage IV KRAS G12C+/IDH1/2- patients compared with 9. 7 months for KRAS G12C+/IDH1/2+ (P = 0. 02). Conclusions: In stage IV KRAS G12C-mutant NSCLC, IDH1/2 co-mutations were linked to shorter median OS. These findings, along with the frequent co-alterations of IDH1/2 with EGFR and KRAS, warrant further study of targeted and combination strategies. Citation Format: Zhaohui L. Arter, Cathleen Park, Misako Nagasaka, Sai-Hong I. Ou,. Pan-cancer landscape of IDH1/2 mutations with a focus on non-small cell lung cancer: Insights from the AACR GENIE Registry abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts) ; 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86 (7 Suppl): Abstract nr 4109.