CD Markers

Author: Nat Pernick, M.D. (see Authors page)

Revised: 7 Janaury 2016, last major update February 2002

Copyright: (c) 2002-2016,, Inc.

PubMed Search: ALK or ALK-1 [title]
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Cite this page: CD246. website. Accessed November 19th, 2019.
Definition / general
  • Also called ALK or ALK-1
  • Anaplastic lymphoma kinase gene at 2p23
  • Is NOT the same as Ki-1/CD30, as indicated by some references
  • Membrane spanning tyrosine kinase receptor; ligand is growth factor pleiotrophin
  • Normally expressed in developing nervous system and weakly in adult nervous system
  • In anaplastic large cell lymphoma, is usually fused with NPM (nucleophosmin) gene via t(2;5)(p23;q35), but also variants (Genes Chromosomes Cancer 2002;34:354)
  • ALK negative cases of primary anaplastic large cell lymphoma are associated with trisomy 2 (Mod Pathol 2005;18:235), consensus criteria for diagnosis are lacking (Am J Clin Pathol 2007;127:707)
  • ALK mutation causes hereditary hemorrhagic telangiectasia type 2 (J Dent Res 2006;85:705)
  • Prognostic significance: ALK+ tumors have favorable prognostic significance in anaplastic large cell lymphomas [ALCL] (Blood 1999;93:3913), including primary CNS ALCL (Am J Surg Pathol 2003;27:487) and inflammatory myofibroblastic tumors (Am J Surg Pathol 2007;31:509)
  • Usually cytoplasmic and nuclear staining
Uses by pathologists
  • Prognostic value in anaplastic large cell lymphoma and inflammatory myofibroblastic tumor (see above), differentiate inflammatory myofibroblastic tumor (ALK+) from ALK negative spindled neoplasms in soft tissue (Am J Surg Pathol 2001;25:1364) and bladder (Mod Pathol 2007;20:592)
Microscopic (histologic) images

Images hosted on other servers:

Anaplastic lymphoma-various images

Diffuse large B cell lymphoma (fig B)

Neuroblastoma (weak)

Alveolar rhabdo-myosarcoma (dot-like cytoplasmic staining-fig B)

Anaplastic lymphoma (fig C)

Inflammatory myofibroblastic tumor #1 of bladder (fig d)

#2 of abdomen (fig 2A)

#3 of larynx
(fig 2c)

#4-site unspecified
(fig B)

#5-site unspecified
(fig A)

Positive staining - normal
  • Embryonic neurons of CNS/PNS; weakly positive in adult brain
Positive staining - tumors
Negative staining
  • Fibromatosis, GIST, nodular fasciitis, normal lymphoid tissue
Additional references
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