Keratin 7

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Protein found in humans

title: "Keratin 7" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["keratins"] description: "Protein found in humans" topic_path: "general/keratins" source: "https://en.wikipedia.org/wiki/Keratin_7" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Protein found in humans ::

Keratin, type II cytoskeletal 7 also known as cytokeratin-7 (CK-7) or keratin-7 (K7) or sarcolectin (SCL) is a protein that in humans is encoded by the KRT7 gene. Keratin 7 is a type II keratin. It is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels.

Function

Keratin-7 is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. The genes encoding the type II cytokeratins are clustered in a region of chromosome 12q12-q13. Alternative splicing may result in several transcript variants; however, not all variants have been fully described.

Keratin-7 is found in simple glandular epithelia, and in transitional epithelium. Epithelial cells of the lung and breast both contain keratin-7, but some other glandular epithelia, such as those of the colon and prostate, do not.

Immunohistochemistry

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/cd/CK7_of_metastatic_carcinoma_to_lymph_node.jpg" caption="Immunohistochemistry for CK7 of a metastatic undifferentiated carcinoma to a lymph node."] ::

Because the keratin-7 antigen is found in both healthy and neoplastic cells, antibodies to CK7 can be used in immunohistochemistry to distinguish ovarian and transitional cell carcinomas (staining positive) from colonic and prostate cancers (negative), respectively. It is commonly used together with CK20 when making such diagnoses. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/00/CK7_and_CK20_by_body_location.svg" caption="CK7 and CK20 expression by various body locations.Image by"] ::

Mikael Häggström, MD. More info at image description page in Wikimedia Commons.]]

References

References

  1. (Aug 1991). "Three epidermal and one simple epithelial type II keratin genes map to human chromosome 12". Cytogenetics and Cell Genetics.
  2. (Jul 2006). "New consensus nomenclature for mammalian keratins". The Journal of Cell Biology.
  3. "Entrez Gene: KRT7 keratin 7".
  4. Leong, Anthony S-Y. (2003). "Manual of Diagnostic Cytology". Greenwich Medical Media, Ltd..

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

keratins