Non–small cell lung cancers with isocitrate dehydrogenase 1 or 2 (IDH1/2) mutations

Abstract

Isocitrate dehydrogenases 1 and 2 (IDH1/2) are important metabolic enzymes that convert isocitrate to α-ketoglutarate. IDH1/2 mutations are associated with the development of multiple malignancies. In this study, we examine the prevalence and features of non-small cell lung cancers (NSCLC) with IDH1/2 mutations. From May 2013 to March 2017, 800 lung cancer samples were successfully sequenced for somatic mutations on the Ion Torrent PGM with the 50-gene AmpliSeq Cancer Hotspot Panel v2 on the Ion Torrent PGM (318 chip). Variants were identified using the Ion Torrent Variant Caller Plugin and reference genome hg19. Golden Helix's SVS software was used for variant annotation and prediction of significance. Nine samples (1.1%) from 8 patients harbored an IDH1 (3 p.R132C and 2 p.R132L) or IDH2 mutation (p.R140W, p.R172S, and p.R172T). All patients' tumors had adenocarcinoma histology, and all patients had a smoking history. Eighty-eight percent of patients' tumors had a coexisting KRAS mutation and 6 of 8 were diagnosed at greater than 70 years of age. Five patients presented with stage IV disease and 3 with stage I. After comparison to a cohort of KRAS-mutated NSCLC with a history of smoking, IDH-mutated cases were significantly older but presented with similar rates of advanced-stage disease and sex distribution. Additional studies are needed to understand the role of IDH1/2 mutations in the development of NSCLC, but such patients who have poor prognostic indicators (KRAS mutation and advanced stage at presentation) may benefit from IDH1/2-directed therapies.