NSCLC ALK mutations, on the other hand, are chromosomal rearrangements.The most common ALK mutation in NSCLC is caused by the echinodermmicrotubule-associated protein-like 4 (EML4) gene’s 5′end juxtaposing with the 3′ end of the ALK gene, resultingin the oncogene EML4–ALK. Here, EML4 is linked to non-small cell lung carcinoma.