1196P - Assessment of Alk Rearrangement in Advanced Non-Small Cell Lung Cancer Using Fluorescence in Situ Hybridization & Immunohistochemistry

Abstract

ABSTRACT Introduction Immunohistochemistry assay (IHC) is recommended to screen non-small cell lung cancer (NSCLC) patients with anaplastic lymphoma kinase (ALK) gene rearrangement, who are candidates for ALK inhibitor therapy in recent studies. However, which cases should be confirmed by Fluorescent in situ hybridization (FISH) is unclear. We investigated ALK rearrangement using IHC and FISH and evaluated the concordance between IHC and FISH testing. Methods One hundred twenty seven paired tumor samples with advanced NSCLC were collected from Cancer Institute/Hospital of Chinese Academy of Medical Sciences. All of these patients who previously received cell cytotoxic regimens therapy had progressive disease. ALK protein was detected by IHC using new clone antibody (D5F3, Cell Signal Techonology, USA). ALK gene rearrangement was evaluated by FISH using Vysis ALK Break Apart FISH Probe kit (Abbott, USA). Results One hundred nineteen samples can be evaluated in 127 cases (93.7%). ALK positive samples were 39.5% (47/119) by IHC, and ALK rearrangement samples were 37.8% (45/119) by FISH. The concordance rate is 95% (kappa = 0.894, p Conclusion IHC can be a useful algorithm to evaluate ALK rearrangement in NSCLC screening for ALK targeted therapy. Our findings suggest that ALK with IHC 1 + and 2 + score should be confirmed by FISH testing. Disclosure All authors have declared no conflicts of interest.