Preliminary Evaluation of the New Tumor Marker, CYFRA 21-1, in Lung Cancer Patients

Serum samples from 137 lung cancer patients were examined byRIA to evaluate the clinical efficacy of the new tumor marker,CYFRA 21-1, which could identify the soluble fragment of cytokeratin19. The cut-off value was determined to be 2.2 ng/ml accordingto the receiver operating characteristic curve. The sensitivity,specificity and accuracy of the RIA for CYFRA 21-1 were 57.7,91.9 and 64.9%, respectively. The serum concentration of CYFRA21-1 and the sensitivity of the assay increased as the diseaseprogressed. Histologically, the sensitivity was highest forsquamous cell carcinomas (SQ) (76.5%) in comparison with adenocarcinomas(47.8%) and small cell lung cancers (42.1%) (P<0.01, P<0.05,respectively). The sensitivities for SQ were 60.0, 83.3, 80.0and 100% at stages I, II, III and IV, respectively. When comparedwith CEA (45.3%) and squamous cell carcinoma related antigen(SCC) (22.6%) in all lung carcinomas, CYFRA 21-1 showed thehighest sensitivity (57.7%), (P<0.05, P<0.01, respectively).In SQ, the sensitivity of the CYFRA 21-1 RIA was significantlyhigher than that of the assay for SCC (47.1%) (P<0.05). Inpatients with adenocarcinomas, the sensitivity of the CYFRA21-1 assay was almost the same as that for CEA (49.3%). In acombination of CYFRA 21-1 and CEA for non-small cell lung cancers(NSCLQ, the sensitivity and accuracy increased to 75.4 and 78.1%,respectively, although the specificity decreased to 86.5%. Itis concluded that CYFRA 21-1 could replace SCC, a less satisfactorytumor marker, for SQ of the lung. The potentiality of the combinationof CYFRA 21-1 and CEA for NSCLC should be estimated using largersamples in the near future