KRT19 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | KRT19 , CK19, K19, K1CS, keratin 19 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 148020; MGI: 96693; HomoloGene: 1713; GeneCards: KRT19; OMA:KRT19 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Keratin, type I cytoskeletal 19 (Keratin-19)) also known as cytokeratin-19 (CK-19) is a 40 kDa protein that in humans is encoded by the KRT19 gene. [5] [6] Keratin-19 is a type I keratin.
Keratin-19 is a member of the keratin family. The keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells and are subdivided into cytokeratins and hair keratins.
Keratin-19 is a type I keratin. The type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains. Unlike its related family members, this smallest known acidic cytokeratin is not paired with a basic cytokeratin in epithelial cells. It is specifically found in the embryonic periderm, the transiently superficial layer that envelops the developing epidermis. The type I cytokeratins are clustered in a region of chromosome 17 (q12-q21). [6]
CYFRA 21-1, a soluble fragment of KRT19, is a tumor marker of various types of cancer, including lung, breast, stomach, pancreas, ovary. KRT19 is commonly expressed in carcinomas of these organs and CYFRA 21-1 is produced when KRT19 is cleaved during cell apoptosis. [7] [8]
Due to its high sensitivity, KRT19 is the most used marker for the RT-PCR-mediated detection of tumor cells disseminated in lymph nodes, peripheral blood, and bone marrow of breast cancer patients. Depending on the assays, KRT19 has been shown to be both a specific and a non-specific marker.
False positivity in CYFRA 21-1 / KRT19 RT-PCR studies include:
Moreover, Ck-19 is widely applied as post-operative diagnostic marker of papillary thyroid carcinoma. [10]
Keratin-19 is often used together with keratin 8 and keratin 18 to differentiate cells of epithelial origin from hematopoietic cells in tests that enumerate circulating tumor cells in blood. [11]