Cytokeratin 1 (CK1, K1)

Stains
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, PathologyOutlines.com, Inc.

PubMed Search: ck1[title]

Table of Contents

Cite this page: Cytokeratin 1 (CK1, K1). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainsck1.html. Accessed July 12th, 2017.

Definition / general

Highest molecular weight keratin (67-68 kDa)
Produced by KRT1 gene in complex manner (PLoS Genet 2006;2:e93)
Associates with CK10
Keratin 1b is expressed in eccrine sweat glands (J Invest Dermatol 2005;125:428)
Reduced expression in HPV infection (Cancer Res 1990;50:3709)
Mutations are associated with epidermolytic hyperkeratosis / bullous congenital ichthyosiform erythroderma (Dermatol Online J 2006;12:6), Greither’s syndrome (J Am Acad Dermatol 2005;53:S225), striate palmoplantar keratoderma (J Invest Dermatol 2002;118:838)

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)

Microscopic (histologic) images

Image hosted on Nature.com:

Eccrine sweat gland expression

Additional references