Dominant cytoskeletal proteins of epithelial cells, which represent the most important part of the cytoskeleton. Cytokeratins (= alpha-keratins; see below keratins) are cytoplasmically localized and belong to the group of intermediate filaments. They can also be expressed in non.epithelial tumors, e.g. leiomyosarcoma, epithelioid angiosarcoma, epithelioid fibrosarcoma. Possible co-expression with other intermediary filaments (e.g. vimentin). Cytokeratins have, among other things, a high diagnostic importance (see CK7, CCK10, CK20 and others) in determining the histogenesis of tumours.
Cytokeratins
DefinitionThis section has been translated automatically.
General informationThis section has been translated automatically.
More than 20 different cytokeratins (CK/ZK) are known. They are classified according to their chemical properties into acidic (TYPE A) or neutral-basic cytokeratins (TYPE B) or according to their molecular weight into high and low molecular cytokeratins. There are a number of antibodies with specificity for individual cytokeratins, several cytokeratins or cytokeratin groups. In the cytoskeleton, a type A-ZK forms a complex with a type B-ZK, so that epithelia always express at least 2 cytokeratins. Antibodies such as KL-1 or MNF-116 are suitable as markers for pancytokeratin, but also the mixture of two antibodies against acidic and basic cytokeratins AE1/AE3.
HistologyThis section has been translated automatically.
Antibodies against individual cytokeratins help to clarify the histogenesis of a tumour (epithelial origin) in the case of a positive immunohistological reaction. Also the lack of detection of cytokeratins in tumors (e.g. in malignant melanoma or in melanocytic nevi) and sometimes also the staining pattern can indicate a certain histogenesis (e.g. punctiform pattern in Merkel cell carcinoma). An expression of cytokeratins is also present in certain sarcomas and has a high diagnostic value in connection with conventional histology and further immune staining. Melanoma metastases can show aberrant cytokeratin formation in about 10% of cases. This finding can also occur in smooth muscle tumours, rhabdomyosarcomas, schwannomas and in anaplastic large cell lymphomas.