NSCLC represent 80% of all new cases of lung cancer. One molecular subtype of NSCLC is the ALK-positive subtype. The anaplastic lymphoma kinase (ALK) is a transmembrane receptor tyrosine kinase. Activation of ALK occurs through the formation of gene fusions and in NSCLC, the gene fusion partner for ALK is primarily EML4. The resulting fusion protein is capable of activating the ALK kinase domain, leading to cell growth. The estimated prevalence for ALK rearrangements in NSCLC is 3-5%, and is more commonly found amongst patients with adenocarcinoma histology, in never smokers and in those who are known to be wild type for EGFR and KRAS.