Clinicopathologic features of EML4-ALK mutant lung cancer

11021 Background: EML4-ALK is a novel fusion oncogene in non-small cell lung cancer (NSCLC). The fusion results from a small inversion within chromosome 2p, leading to expression of a constitutively activated, chimeric tyrosine kinase. The clinicopathologic features of these patients have not been definitively established. Furthermore, the clinical outcome of these patients is unknown. Here we present the largest series of EML4-ALK mutants to date, and the first analysis of treatment response and survival in metastatic patients with and without EML4-ALK. Methods: Patients with NSCLC were selected for genetic screening based on 2 or more of the following characteristics: female gender, Asian ethnicity, never or light smoking history, and adenocarcinoma histology. The EML4-ALK inversion was identified using FISH and confirmed by IHC for ALK expression. EGFR mutation status was determined by direct sequencing of EGFR exons 18–21. Results: Of 141 patients screened, 18 (13%) were ALK mutant, 31 (22%) were EGFR...