CLINICAL USEFULNESS OF SERUM CYTOKERATIN-19 FRAGMENT AS A TUMOR-MARKER FOR LUNG-CANCER

Serum soluble cytokeratin 19 fragment (CYFRA) levels were measured in 251 patients with lung cancer and 139 patients with benign lung diseas es to determine the clinical usefulness of CYFRA level determination i n the diagnosis and monitoring of lung cancer. Serum levels of CYFRA w ere measured by a 2-step sandwich ELISA method, When the cut-off value was defined as 3.5 ng/ml, which was associated with a specificity of 95% for benign lung diseases, CYFRA had a high sensitivity (53%) in al l patients with lung cancer, Both the serum level of CYFRA and its sen sitivity increased significantly with the increase in clinical stage, A comparison of areas under receiver operating characteristic curves s howed that CYFRA had the most power of discrimination in the diagnosis of lung cancer among markers including carcinoembryonic antigen, squa mous cell carcinoma antigen, carbohydrate antigen 19-9, and neuron-spe cific enolase. A. good correlation was found between serial changes in serum CYFRA levels during therapy and clinical responses for 18 patie nts who underwent chemotherapy and/or radiotherapy, Our findings sugge st that CYFRA may be a marker of choice for screening and monitoring o f lung cancer, particularly squamous cell carcinoma.