EML4-ALK variant-specific genetic interactions shape lung tumorigenesis

Oncogenic fusions of EML4 and ALK occur in ~5% of lung adenocarcinomas. EML4-ALK variants have distinct breakpoints within EML4, but the functional differences among these variants remain poorly understood. Here we use CRISPR/Cas9 somatic genome editing to generate autochthonous mouse models of the two most common EML4-ALK variants and show that V3 is more oncogenic than V1. By employing multiplexed genome editing and quantifying the effects of 29 putative tumor suppressor genes on V1- and V3-driven lung cancer growth in vivo we show that many tumor suppressor genes have dramatically variant-specific effects on tumorigenesis. Pharmacogenomic analyses suggest that tumor genotype can also modify responses to therapy. Analysis of a large human EML4-ALK lung cancer cohort identified differences in the genomic landscape depending on the EML4-ALK variant. These findings demonstrate functional heterogeneity between EML4-ALK variants, suggesting that EML4-ALK variants behave more like distinct oncogenes than a uniform entity. More broadly, these findings highlight the dramatic impact of oncogenic fusions partner proteins and coincident tumor suppressor gene alterations on the biology of oncogenic fusion driven cancer.