This gene encodes a receptor tyrosine kinase which belongs to the insulin receptor superfamily This protein comprises an extracellular domain an hydrophobic stretch corresponding to a single pass transmembrane region and an intracellular kinase domain It plays an important role in the development of the brain and exerts its effects on specific neurons in the nervous system This gene has been found to be rearranged mutated or amplified in a series of tumours including anaplastic large cell lymphomas neuroblastoma and non-small cell lung cancer The chromosomal rearrangements are the most common genetic alterations in this gene which result in creation of multiple fusion genes in tumourigenesis including ALK (chromosome 2) EML4 (chromosome 2) ALK RANBP2 (chromosome 2) ALK ATIC (chromosome 2) ALK TFG (chromosome 3) ALK NPM1 (chromosome 5) ALK SQSTM1 (chromosome 5) ALK KIF5B (chromosome 10) ALK CLTC (chromosome 17) ALK TPM4 (chromosome 19) and ALK MSN (chromosome X)