ALK and anaplastic large cell lymphoma: The Anaplastic lymphoma kinase (ALK) gene, originally identified as part of the chimeric nucleophosmin-ALK (NPM-ALK) protein in a chromosomal rearrangement associated with anaplastic large cell lymphoma [228], maps to chromosome 2p23 and encodes a tyrosine kinase receptor normally expressed at high levels in developing central and peripheral nervous systems districts, such as thalamic nuclei, spinal cord motoneurons and sympathetic, enteric ganglia and motor nuclei of the brainstem [229,230,231,232].