Non-structural role of cytokeratins in malignant neoplasms

Cytokeratins (CKs) are well studied as intermediate filaments of the cytoskeleton of epithelial cells, providing specific cell structure and morphology, in particular, apico-basal cell polarization. Meanwhile, a certain specificity of the association of CK with different types of epithelia is noted. CK heterogeneity in the glandular epithelium is particularly pronounced and is associated with anatomical localization. The relative specificity of CKs in epithelium of different localization is preserved to a great extent in carcinomas originating from this epithelium as well. Due to this fact the determination of CK spectrum in tumor cells is quite an effective tool for nosological diagnostics of carcinomas. however, the function of CKs is not limited to providing the cell structure. The presence and amount of CK changes during the most important processes in normal and tumor cells: movement/invasion, apoptosis, proliferation, epithelial-mesenchymal plasticity. A question arises: Is initiation of the above-listed processes happens first, and therefore CK changes are secondary and «passive», or in some processes CK changes can play a role of a trigger? Knowing the answer to this question is not only of fundamental importance, but is also important for finding ways to control the above processes by influencing the CKs.