For EGFR and ALK genes, the significance of respective mutations and translocations are clear, but the importance of gene copy number changes are not. Reporting in J Thorac Oncol. 2011;6: 21-27 senior author Edurne Arriola and coauthors investigate the relationship of ALK and EGFR gene status in pulmonary adenocarcinomas.
Using fluorescence in situ hybridization (FISH) to confirm that ALK gene translocations are infrequent in pulmonary adenocarcinomas, the authors prove that ALK gene amplifications and copy number gains are common, especially when assayed in larger resection specimens. In this series, ALK amplification did not show prognostic significance for overall survival. This study contrasts with previous analysis of tissue microarrays and small biopsies, which showed low prevalence of ALK gene amplifications, most likely related to a low relative number of tumor cells with ALK amplification and increased likelihood of detection in larger resection samples. Oncologists will ask about the significance of ALK gene amplifications and copy number gains in lung adenocarcinomas. For now, there is no proven significance.
Editorial. Guy E.Nichols MD, PhD.