Introduction The purpose of this study was to investigate the clinical characteristics and treatment outcomes of patients with anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) to conventional chemotherapy in the pre-ALK inhibitor era Patients and Methods We retrospectively screened 381 consecutive NSCLC patients without known epidermal growth factor receptor (EGFR) or KRAS mutation who were diagnosed between 2007 and 2008 at a single center, and identified ALK rearrangements by fluorescence in situ hybridization Additional 44 ALK-positive patients from other period were included for the analysis of clinical outcomes Results Of the 381 tumors screened, four were excluded because the samples were unevaluable Twenty-one (5 6%) showed ALK rearrangements, with twenty adenocarcinomas and one pleomorphic carcinoma Of the entire 65 ALK-positive patients, 32 patients received pemetrexed as a second- or further-line therapy, in whom response rate was 34 4% (11/32) and median progression-free survival (PFS) was 4 0 months Among these 31 patients, 20 specimens were available for thymidylate synthase (TS) expression analysis Low expression of TS were found in 80% (16/20), with a trend toward longer PFS than TS-positive patients (median PFS 4 0 vs 1 0 months, P = 0 095) Conclusions The prevalence of ALK rearrangement was 5 6% among EGFR and/or KRAS wild-type/unknown NSCLC population Low TS protein expression might be associated with better clinical outcomes in ALK-positive NSCLC patients after pemetrexed given as a second- or further-line therapy

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1718. doi:1538-7445.AM2012-1718