The ALK translocation in advanced non-small-cell lung carcinomas: preapproval testing experience at a single cancer centre.

Overview

AIMS: To study the ALK translocation in patients with advanced non-small-cell lung carcinomas (NSCLCs) seen at a European cancer centre, and its association with EGFR mutations, KRAS mutations and MET amplification. METHODS AND RESULTS: The study included samples from 86 patients diagnosed with advanced NSCLC. ALK fluorescence in-situ hybridization (FISH) was performed using the ALK break-apart probe set (Vysis). ALK FISH-positive cases were defined as those with more than 15% break-apart signals or isolated red signals in 50 cells. EGFR and KRAS mutations were determined by direct sequencing. All ALK-positive cases were analysed retrospectively for MET amplification using a FISH assay, and for ALK mutations by sequencing. We found nine (10.5%) ALK-positive cases, all in adenocarcinomas and the majority in female patients (88.9%). Signet ring cells were observed in four (44.4%) of the nine patients. None of the ALK translocated cases showed MET amplifications or EGFR, KRAS and ALK mutations. CONCLUSIONS: The prevalence of ALK translocation in an unselected population of European patients with advanced NSCLCs was 10%. This alteration was mutually exclusive with EGFR and KRAS mutations, as well as with MET amplification. If multiplexing is considered at the preanalytical phase, lung biopsy specimens are sufficient for performing several predictive assays.