Anaplastic lymphoma kinase receptor (ALK)

Anaplastic lymphoma kinase receptor (ALK) is a transmembrane receptor tyrosine kinase belonging to the insulin receptor superfamily. It consists of an extracellular ligand-binding domain with unique features—including two MAM domains and one LDL class A domain—a single transmembrane helix, and an intracellular tyrosine kinase domain[1][2][5]. Physiologically expressed mainly during embryonic neural development with low levels postnatally in humans[3], it mediates neuronal differentiation via pathways like MAPK. Pathologically, chromosomal rearrangements involving the ALK gene result in constitutively active fusion proteins such as NPM–ALK or EML4–ALK that drive oncogenesis across several cancers including anaplastic large-cell lymphoma (~60% are "ALK-positive"), subsets of non-small cell lung cancer (~5%), neuroblastoma (familial cases often harbor germline activating mutations), inflammatory myofibroblastic tumors, among others[2][3][6]. Targeted inhibition of aberrant ALK activity has become a mainstay for treating these malignancies using specific small-molecule inhibitors. Detection of genetic alterations involving ALK serves both diagnostic and therapeutic purposes. Resistance mechanisms remain a clinical challenge requiring ongoing research into next-generation inhibitors. In summary: > Anaplastic lymphoma kinase is a membrane-bound enzyme-receptor critical for neural development but best known as an oncogenic driver when mutated or fused with other genes; it is therapeutically targeted by several approved drugs primarily in oncology settings.[2][3][6]

Other names

CD246ALK receptorALK tyrosine kinaseNPM-ALK (for fusion protein)EML4-ALK (for fusion protein)

Drugs targeting ALK typically act as small-molecule inhibitors that bind to the intracellular tyrosine kinase domain of the receptor. This inhibits its phosphorylation activity and downstream oncogenic signaling pathways such as Ras/Raf/MEK/ERK and JAK/STAT[3][7].