Cytokeratin 1 (CK1, K1)

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

Revised: 4 December 2015, last major update October 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: ck1[title]
Cite this page: Cytokeratin 1 (CK1, K1). website. Accessed March 26th, 2017.
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)
Micro Images

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Eccrine sweat gland expression

Additional References