Keratin 7

Template:Short description Template:Infobox gene 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.<ref name="pmid1713141">Template:Cite journal</ref><ref name="pmid16831889">Template:Cite journal</ref><ref name="entrez">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name="entrez"/>

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

File:CK7 of metastatic carcinoma to lymph node.jpg

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.<ref name=Leong>Template:Cite book</ref>

File:CK7 and CK20 by body location.svg

CK7 and CK20 expression by various body locations.<ref>Image by Mikael Häggström, MD. More info at image description page in Wikimedia Commons.</ref>

Further reading

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