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Testing for ALK Gene Rearrangement

Testing for ALK

Having established the importance of testing for anaplastic lymphoma kinase (ALK) gene rearrangements in non-small cell lung cancer (NSCLC), this section will provide evidence-based guidance on who should be tested, when they should be tested, and how to perform the tests.

We have already learned that the decision on whether or not to test a patient for ALK should not be based on clinical characteristics alone; it is important to identify all patients with ALK-positive disease. Furthermore, rapid diagnostic procedures and treatment decisions are essential for patients with advanced NSCLC; therefore, effective collaboration between oncologists and pathologists is key to ensuring all patients are tested at initial diagnosis for all relevant molecular markers.

According to current guidelines from the European Society for Medical Oncology (ESMO)1,2 and from the College of American Pathologists (CAP), the International Association for the Study of Lung Cancer (IASLC) and the Association for Molecular Pathology (AMP):3

  • ALK testing should be carried out systematically in advanced non-squamous NSCLC
  • All advanced NSCLC patients should be tested for ALK at initial diagnosis, allowing patients to receive the most appropriate treatment as early as possible
  • It is preferable to test for different molecular markers in parallel as sequential testing may delay treatment and is a less efficient use of limited tissue samples
  • Molecular test results should be available within 10 working days of receiving the specimen in the testing laboratory

Watch the video clip below to see Professor Keith Kerr of the University of Aberdeen discuss the ESMO guidelines on testing for ALK in NSCLC.


ALK testing is also recommended in all patients with lung adenocarcinoma by the National Comprehensive Cancer Network (NCCN) panel.4

Click on the icons below to read published guidance on molecular testing in NSCLC.

Due to an increasing number of molecular tests that should be performed from NSCLC specimens, tissue sample size should be maximised whenever possible. Tissue handling, processing and sectioning should be standardised to minimise wastage and optimised for the staining procedures and PCR-based molecular tests required for NSCLC. Histological and cytological specimens are both potentially suitable for ALK testing. If the initial tissue sample is small, 3 to 4 spare sections should be cut upfront to avoid tissue loss from re-cutting.

Click the image below to access the IASLC Atlas of ALK Testing in Lung Cancer.