CYFRA 21-1 - A NEW TUMOR-MARKER FOR LUNG-CANCER

Among 20 known cytokeratins, cytokeratin fragment 19 is a 40 kD acidic molecule whose distibution is restricted to simple or pseudo-stratifi ed epitelia, such as the epithelial layer of the bronchial tree. An im munoradiometric assay, CYFRA 21-1, was used to detect a fragment of cy tokeratin 19 in the serum of 90 subjects and compared with serum level s of CEA, NSE and TPA. Sixty-seven consecutive patients with lung canc er and 23 healthy subjects were tested. Cut-off values for tumor marke rs were considered as the 95% of specificity versus controls. There we re 32 adenocarcinomas, 29 squamous carcinomas and 6 other tumors. Incr eased serum levels of CYFRA 21-1 were found in lung cancer patients co mpared to controls [1.6 (0.2-3.2) versus 0.5 (0.2-1.8): p<0.001]. In o ur study TPA was more sensitive than CYFRA 21-1: 49% versus 40%; when we combined both markers the sensitivity increased to 63%. Significant difference in values were found before and after surgery in serum lev els of 34 operated patients: p<0.01. We found higher levels of soluble cytokeratin 19 in lung cancer patients and in the adenocarcinoma subg roup. This study does not support the exclusive use of soluble cytoker atin 19 as a specific marker of lung cancer and not only in squamous c arcinoma subgroup. This suggested that diagnostic and prognostic sensi tivity increase when CYFRA 21-1 and TPA or other markers are combined.