An Erbb2 Splice Variant Lacking Exon 16 Drives Lung Carcinoma

Lung cancer causes more deaths annually than any other malig-nancy. A subset of non-small cell lung cancer (NSCLC) is driven by amplification and overexpression or activating mutation of the receptor tyrosine kinase (RTK) ERBB2. In some contexts, notably breast cancer, alternative splicing of ERBB2 causes skipping of exon 16, leading to the expression of an oncogenic ERBB2 isoform (ERBB2 Delta Ex16) that forms constitutively active homodimers. How-ever, the broader implications of ERBB2 alternative splicing in human cancers have not been explored. Here, we have used genomic and transcriptomic analysis to identify elevated ERBB2 Delta Ex16 expression in a subset of NSCLC cases, as well as splicing site mutations facilitating exon 16 skipping and deletions of exon 16 in a subset of these lung tumors and in a number of other carcinomas. Supporting the potential of ERBB2 Delta Ex16 as a lung cancer driver, its expression transformed immortalized lung epithelial cells while a transgenic model featuring inducible ERBB2 Delta Ex16 specifically in the lung epithelium rapidly developed lung adenocarcinomas following transgene induction. Collectively, these observations indicate that ERBB2 Delta Ex16 is a lung cancer oncogene with potential clinical importance for a proportion of patients.