A novel break site of EML4‐ALK report and a rare PRKAR1A‐ALK report analyzed by different ALK detection platforms in non‐small cell lung cancer patients

BACKGROUND: detection of anaplastic lymphoma receptor tyrosine kinase gene (ALK) rearrangements in patients with non‐small‐cell lung cancer (NSCLC) has become a routine pathological diagnosis worldwide. METHODS: there are three major conventional diagnostic methods for ALK fusions: fluorescent in situ hybridization (FISH); immunohistochemistry (Ventana IHC (D5F3)); and polymerase chain reaction (PCR). Next‐generation sequencing (NGS) technology as is a new tool for ALK status detection with great potential. These four methods are highly consistent in detecting ALK status (coincidence rate >96%). However, discrepancies in ALK status have been found in some patients among these methods, which causes confusion for clinicians. RESULTS AND CONCLUSION: in this study, we analyzed two patients whose ALK statuses were not consistent using these four methods. We explored the potential reasons for deviation of the test results and found a novel EML4‐ALK break site, which had been not described previously.