Nucleophosmin-anaplastic lymphoma kinase fusion protein (NPM-ALK) (NPM-ALK)

The Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion protein is an oncogenic tyrosine kinase resulting from the t(2;5)(p23;q35) chromosomal translocation (Morris et al., 1994, Science). This translocation fuses the N-terminal dimerization domain of nucleophosmin (NPM1) to the intracellular catalytic domain of the anaplastic lymphoma kinase (ALK) (Chiarle et al., 2008, Nature Reviews Cancer). The NPM1 portion facilitates constitutive dimerization, leading to the ligand-independent activation of the ALK kinase domain. This activation triggers multiple oncogenic signaling pathways, including STAT3, PI3K/AKT, and MAPK/ERK, which drive uncontrolled cell proliferation and survival (Werner et al., 2017, Leukemia). NPM-ALK is the primary driver in approximately 75% of cases of anaplastic large cell lymphoma (ALCL) (Amin & Lai, 2007, Blood). Therapeutic strategies focus on small-molecule ALK inhibitors like crizotinib and alectinib that compete with ATP for the kinase binding site (Mossé et al., 2013, JCO). While initially effective, clinical challenges include the development of secondary mutations in the kinase domain, such as G1202R, that confer drug resistance (Gainor et al., 2016, Cancer Discovery). Monitoring for the fusion protein via immunohistochemistry or fluorescence in situ hybridization is standard for diagnosing ALK-positive ALCL.

Other names

NPM1-ALKp80t(2;5)(p23;q35) fusion proteinNucleophosmin-ALK

ATP-competitive inhibition of the ALK tyrosine kinase domain (Mossé et al., 2013)