EML4-ALK Variant-Specific Genetic Interactions Shape Lung Tumorigenesis.

Diverse fusions of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) are oncogenic drivers in lung adenocarcinoma. EML4-ALK variants have distinct breakpoints within EML4, but their functional differences remain poorly understood. In this study, we use somatic genome editing to generate autochthonous mouse models of EML4-ALK-driven lung tumors and show that variant 3 (V3) is more oncogenic than variant 1 (V1). By using multiplexed genome editing and quantifying the effects of 29 putative tumor-suppressor genes on V1- and V3-driven lung cancer growth, we show that many tumor-suppressor genes have variant-specific effects on tumorigenesis. Pharmacogenomic analyses further suggest that tumor genotype can influence therapeutic responses. Analysis of human EML4-ALK-positive lung cancers also identified variant-specific differences in their genomic landscapes. These findings suggest that EML4-ALK variants behave more like distinct oncogenes than a uniform entity and highlight the dramatic impact of oncogenic fusion partner proteins and coincident tumor-suppressor gene alterations on the biology of oncogenic fusion-driven cancers. SIGNIFICANCE: EML4-ALK-driven lung cancer is treated as a uniform disease despite the presence of distinct fusion variants in patients. Our findings show that EML4-ALK variants are functionally distinct, which may have implications for the treatment of this cancer type and highlights the need to consider differences among variants of other oncogenic fusions.