Keratin 19 fragment

Cytokeratin is the middle filament of the cell body and is the main component of the cell structure. It can be divided into 20 different types according to its molecular weight and the electric point of two-dimensional two-dimensional electrophoresis. Differentially expressed epithelial cells. CYFRA21-1 is composed of two monoclonal antibodies of cytokeratin 19 fragment, namely monoclonal antibodies BMl9-21 and KSl9.1, which is an acidic cell protein with a molecular weight of 4kD. It is mainly distributed in the cytoplasm of monolayer and stratified epithelial tumor cells. When the cells die, it is released into the serum as lysed fragments.