ALK immunohistochemistry positive, FISH negative NSCLC is infrequent, but associated with impaired survival following treatment with crizotinib

Objective: Metastasized non-small cell lung cancer (NSCLC) with an anaplastic lymphoma kinase (ALK) rearrangement is usually sensitive to a range of ALK-tyrosine kinase inhibitors. ALK-positive NSCLC have been identified in pivotal phase III trials with fluorescence in situ hybridization (ALK FISH+). These tumors are also expressing the fusion product (ALK immunohistochemistry (IHC)+). However, discrepant cases occur, including ALK IHC + FISH-. The aim of this study was to collect ALK IHC + cases and compare within this group response to crizotinib treatment of ALK FISH + cases with ALK FISH- cases. Conclusion: ALK IHC + FISH- NSCLC is infrequent and associated with a worse outcome on personalized treatment. A suitable predictive testing strategy may be to screen first with IHC and then confirm with FISH instead of considering ALK IHC equivalent to ALK FISH according to the current guidelines. READ ARTICLE

Lung Cancer
DOI:10.1016/j.lungcan.2019.09.023

Authors: E. Thunnissen, B.I. Lissenberg-Witte, M.M. van den Heuvel, K. Monkhorst, B.G. Skov, J.B. Sørensen, A. Mellemgaard, A.M.C. Dingemans, E.J.M. Speel, A.J. de Langen, S.M.S. Hashemi, I. Bahce, M.A. van der Drift, M.G. Looijen-Salamon, J. Gosney, P.E. Postmus, S.M.S. Samii, F Duplaquet, B. Weynand, X. Durando, F. Penault-Llorca, S. Finn, A.O Grady, B. Oz, N. Akyurek, R. Buettner, J. Wolf, L. Bubendorf, S. Duin, I. Marondel, L.C. Heukamp, W. Timens, E.M.D. Schuuring, P. Pauwels, E.F. Smit