Cytokeratin-19 fragment (CYFRA 21-1) in bladder cancer

The present study was designed to evaluate the role of the cytokeratin-19 fragment (CYFRA 21-1) as a tumor marker in bladder cancer. The bladder cancer cell line JMSU1 was used in the preclinical study. Subjects comprised 120 healthy volunteers, 20 patients with benign bladder diseases including acute cystitis and bladder stones, 12 patients with chronic renal failure, and 117 patients with histologically confirmed primary bladder cancer. CYFRA 21-1 concentrations were measured by a sandwich enzyme-linked immunosorbent assay. The preclinical study in vitro and in vivo showed that JMSU1 produced and released CYFRA 21-1 in the culture supernatants and serum of JMSU1-bearing nude mice. The cutoff level was set at 3.5 ng/ml (mean + 3 SD) by the analysis in the healthy volunteers. Under this condition, sensitivity was 0% in benign bladder diseases, 83% in chronic renal failure, and 41.9% in bladder cancer. Serum CYFRA 21-1 levels increased significantly as tumor stage advanced or tumor grade increased. A serial follow-up study demonstrated that patients with progressive disease showed a gradual increase in serum CYFRA 21-1 levels while patients who responded to the treatments had a marked decrease in serum CYFRA 21-1 levels. Higher serum CYFRA 21-1 levels were related to poor survival. The present study suggests that serum CYFRA 21-1 is a useful marker to monitor the clinical course of bladder cancer and to provide prognostic information.