[Cytokeratin detection as a diagnostic tool in oncology]

A large part of the cell cytoplasm of the cells consists of components forming cytoskeleton. The cytoskeleton is represented by actin-containing microfilaments, tubulin-containing microtubules and filaments of intermediate size. The last ones have diameters between 7-11 nm. Based on morphological, immunological and biochemical criteria the filaments of intermediate size are divided into: a) nuclear lamins; b) neurofilaments which are typical for neuronal cells; c) vimentin and vimentin-like filaments present especially in mesenchyma derived cells and d) filaments containing keratin-like proteins--cytokeratins. Cytokeratin filaments are a family of many different polypeptides and are normal components of epithelial cell cytoskeleton. Cytokeratins are expressed in various types of epithelia in different combinations. This is why antibodies against various cytokeratins have been used to characterize a wide variety of epithelial tumors. For example immunohistochemical detection of cytokeratin can identify micrometastases, not detected by conventional hematoxylin and eosin staining. Also serum cytokeratins levels are widely used as the markers of tumors of epithelial origin. In this review clinical applications of cytokeratins detection are presented.