FISH is better suited than molecular testing to detect the spectrum of variants of ALK and ROS1 rearrangements. The ALK gene has more than 20 known rearrangement partner genes, with 15 variants of the most common EML4-ALK fusion. ROS1 has seven partners described so far in NSCLC. While molecular assays must be designed to individual and unique fusions, FISH detection encompasses all described and as yet undescribed rearrangements. Patients positive for EGFR mutations benifit from Tyrosine kinase inhibitors (Gefitinib).