Anaplastic lymphoma kinase protein

The "anaplastic lymphoma kinase protein" expresses the ALK/NPM fusion protein p80. Expression of the ALK protein results from a chromosomal translocation, most commonly between chromosomes 2 and 5 (p23;q35), resulting in the fusion of the nuclear phosphoprotein nucleophosmin (NPM) with the intracellular domain of the receptor kinase ALK.   

Detection of this protein is helpful in the diagnosis of systemic anaplastic large cell lymphoma (ALCL) with the t(2;5) translocation.

In normal tissue, ALK expression occurs only in central nervous system tissue (thalamus, ganglia, ganglion cells, etc.).

Detection of the anaplastic lymphoma kinase protein is negative in lymphomatoid papulosis and primary cutaneous CD30+ ALCL.