CYFRA21-2 is an antigenic determinant which represents a fragment of the 40kD protein Cytokeratin 19. This antigen is defined and measured in serum by using two mouse monoclonal antibodies; KS 19-1 and BM 19-21. Both are reactive to epitopes 1 and 21 of cytokeratin 19 (thus this cytokeratin 19 fragment is named as CYFRA21-1). CYFRA21-1 is a tumor marker based on the determination of water-soluble cytokeratin 19 which is secreted by normal or malignantly transformed epithelial cells.

This antibody detects both synthetic peptide and cellular proteins from tested cancer cell lines (Hela, HCF-7 and Hep G2). No cross reactivity with other proteins was found.

Store at -20^°C if not intended for use within a month. May keep at 4^°C for a month. Minimize freezing and thawing during use.

The antibody is stable for at least a year from the date of receipt when stored at -20^°C to -70^°C. Reconstituted antibody (suggested with steril PBS) can also be aliquoted and stored frozen at -20^°C to -70^°C in a manual defrost freezer for months without detectable loss of activity. Upon reconstitution, the antibody can be stored over a month at 4^°C.

Stieber P, Zimmermann A, Reinmiedl J, Muller C, Hoffmann H, Dienemann H. CYFRA 21-1 in the early diagnosis of recurrent disease in non small cell lung carcinomas (NSCLC). Anticancer Res (1999)

Pujol JL, Molinier O, Ebert W, Daures JP, Barlesi F, Buccheri G, Paesmans M, Quoix E, Moro-Sibilot D, Szturmowicz M, Brechot JM, Muley T, Grenier J. CYFRA 21-1 is a prognostic determinant in nonsmall-cell lung cancer: results of a meta-analysis in 2063 patients. BR J Cancer (2004)