According to the updated molecular testing guidelines for the selection of lung cancer patients for treatment with targeted tyrosine kinase inhibitors recommended by the College of American Pathologists, the International Association for the Study of Lung Cancer and the Association for Molecular Pathology in 2017 [68], as well as the FDA having approved the VENTANA ALK (D5F3) CDx Assay (Roche Diagnostics) for a qualitative detection of ALK protein in NSCLC tissue specimens, both ALK FISH and the ALK IHC are considered as the first line methods for ALK rearrangement testing. This evidence concerns the gene ALK and non-small cell lung carcinoma.