Immunohistochemistry and fluorescence in-situ hybridization study for detection of anaplastic lymphoma kinase gene rearrangement in nonsmall cell lung carcinoma

Abstract

Patients and methods Testing for Anaplastic Lymphoma Kinas (ALK) rearrangement is now recommended for selection of lung cancer patients targeted for Tyrosine-kinase inhibitors (Crizotimib). We used Fluorescence in situ hybridization (FISH) compared with Immunohistochemical (IHC) staining method to evaluate ALK gene rearrangement and ALK protein expression respectively in twenty cases of thoroughly diagnosed non-small cell lung cancer (NSCLC). The frequency and clinicopathological features of lung cancer harboring ALK rearrangement were reported. Results Histologically, 6 cases were adenocarcinoma and 14 were squamous cell carcinoma type. ALK IHC staining results was positive in 6 out of 20 (30%) using ALK/p80 (Clone SP8, Thermo scientific) monoclonal antibody. ALK rearrangement was detected in only 4 (20%) cases by FISH testing. Negative results were seen in the same 14 (70%) NSCLC cases by using both IHC and FISH techniques. Conclusion IHC may provide an effective strategy for detecting ALK gene changes, but it has false positive results necessitate further confirmatory FISH analysis which can be considered a gold standard method for ALK gene rearrangement detection. ALK gene rearrangement is highly associated with young aged men, non/light smokers and in those having more aggressive clinicopathological features.