Clinicopathological Characteristics of RET Rearranged Lung Cancer in European Patients

Introduction: Rearrangements of RET are rare oncogenic events in patients with non-small cell lung cancer (NSCLC). While the characterization of Asian patients suggests a predominance of nonsmokers of young age in this genetically defined lung cancer subgroup, little is known about the characteristics of non-Asian patients. We present the results of an analysis of a European cohort of patients with RET rearranged NSCLC. Methods: Nine hundred ninety-seven patients with KRAS/EGFR/ALK wildtype lung adenocarcinomas were analyzed using fluorescence in situ hybridization for RET fusions. Tumor specimens were molecularly profiled and clinicopathological characteristics of the patients were collected. Results: Rearrangements of RET were identified in 22 patients, with a prevalence of 2.2% in the KRAS/EGFR/ALK wildtype subgroup. Co-occurring genetic aberrations were detected in 10 patients, and the majority had mutations in TP53. The median age at diagnosis was 62 years (range, 39-80 years; mean +/- SD, 61 +/- 11.7 years) with a higher proportion of men (59% versus 41%). There was only a slight predominance of nonsmokers (54.5%) compared to current or former smokers (45.5%). Conclusions: Patients with RET rearranged adenocarcinomas represent a rare and heterogeneous NSCLC sub-group. In some contrast to published data, we see a high prevalence of current and former smokers in our white RET cohort. The significance of co-occurring aberrations, so far, is unclear. (C) 2015 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.