Cytokeratin 1 (CK1, K1)

Topic Completed: 1 October 2013

Minor changes: 4 March 2019

Copyright: 2003-2018,, Inc.

PubMed Search: ck1[title]

Nat Pernick, M.D.
Page views in 2019: 155
Page views in 2020 to date: 114
Cite this page: Pernick N. Cytokeratin 1 (CK1, K1). website. Accessed August 14th, 2020.
Definition / general
Uses by pathologists
  • No significant clinical use by pathologists
Positive staining - normal
  • Endothelial cells, skin and other squamous epithelium (suprabasal spinous and granular layers), thymic Hassal’s corpuscle
Positive staining - disease
  • Angiosarcoma (73%), epithelioid hemangioendothelioma (100%), epithelioid sarcoma (70%), hemangioma (often), schwannoma (62%), squamous cell carcinomas-keratinizing, synovial sarcoma (28%), vascular tumors (greater in well versus poorly differentiated tumors)
Additional references
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