Cyfra 21-1 – cytokeratin fragment 19 (lung cancer)

General Information

Cytokeratin fragment 19 antigen (CYFRA 21-1) belongs to the cytokeratin protein family, which is mainly synthesized in epithelial tissue and forms the cytoskeleton of epithelial cells.

CYFRA 21-1 is used as a tumor marker, especially in non-small cell lung cancer, along with carcinoembryonic and squamous cell antigens. Also for other epithelial tumors such as bladder carcinoma. An increase in its concentration during a tumor is associated with cell lysis (breakdown), after which cytokeratin degradation products are released into the blood.

As other tumor markers, CYFRA 21-1 screening and diagnostic value is less, it is used to evaluate the progress of the treatment for predicting the disease.

CYFRA 21-1 is a relatively new marker defined by 2 monoclonal antibodies directed against cytokeratin fragment 19.

Immunohistochemical studies have confirmed that cytokeratin 19 is mainly found in lung carcinomas, so it is used as a marker of non-small cell lung cancer.

When is the survey conducted?

• When non-small cell lung cancer is suspected
• When differentiating volumetric lung formations of unknown genesis
• For the therapeutic control of non-small cell lung cancer, especially during tumor resection, to assess the likelihood of recurrence
• For predicting bladder tumors

Preliminary preparation: no need

Material for examination:  Venous blood

Reference norms:  <3.3 ng/ml

CYFRA 21-1 is not used for lung cancer screening in asymptomatic patients or in high-risk groups (eg smokers).

Since cytokeratin 19 (CYFRA 21-1) is not an organ-specific marker, its increase in other volumetric processes is also possible.

Factors that may cause inaccuracy of answers:

• Treatment with high doses of biotin (>5 mg/day). It is recommended to stop taking the medicine at least 8 hours before the study.
• High titer of anti-streptavidin and anti-ruthenium antibodies.
• Monoclonal antibodies administered for therapeutic purposes