title: Evaluation of cytokeratin 19 fragment (CYFRA 21-1) as a tumor marker in malignant pleural effusion.
abstract: BACKGROUND
  The aim was to investigate the diagnostic utility of CYFRA 21-1 (cytokeratin 19 fragment) as a tumor marker in pleural effusion and evaluate the value of combining CYFRA 21-1 and carcinoembryonic antigen (CEA) assays as a diagnostic aid in the malignant pleural effusion.
  
  
  METHODS
  One hundred and twenty-six patients (72 malignant and 54 benign pleural effusion) were included in this retrospective study. The effusion levels of CYFRA 21-1 and CEA were measured using radioimmunometric assay.
  
  
  RESULTS
  The median values of CYFRA 21-1 in benign and malignant pleural effusion are 15 and 70 ng/ml, respectively. Using a cut-off value of 50 ng/ml, defined at 94% specificity, the diagnostic sensitivity of CYFRA 21-1 for non-small cell lung carcinoma (n = 61), squamous cell carcinoma (n = 21), adenocarcinoma (n = 40) and small cell lung cancer (n = 11) was 64, 71, 60 and 18%, respectively. Regardless of cell types, the diagnostic sensitivity of CYFRA 21-1 and CEA in malignant pleural effusion (n = 72) was 57 and 60%, respectively (cut-off value of 10 ng/ml in CEA assay). Combining CEA with CYFRA 21-1, the diagnostic sensitivity may increase up to 72%, which was defined at 89% specificity.
  
  
  CONCLUSIONS
  CYFRA 21-1 assay may be a useful tumor marker for discriminating benign from malignant pleural effusion, especially in those of non-small cell lung cancer. The combined use of CEA and CYFRA 21-1 assay in the malignant effusion may increase the diagnostic yield compared with CEA or CYFRA 21-1 alone.
authors.affiliation: Department of Medicine, Veterans General Hospital-Kaohsiung, Taiwan. lairs@ksts.seed.net.tw
authors.forename: R S
authors.initials: RS
authors.lastname: Lai
authors.forename: C C
authors.initials: CC
authors.lastname: Chen
authors.forename: P C
authors.initials: PC
authors.lastname: Lee
authors.forename: J Y
authors.initials: JY
authors.lastname: Lu
mesh_terms: D000951:Antigens, Neoplasm / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis; D018288:Carcinoma, Small Cell / Q000175:diagnosis; D006801:Humans; D053539:Keratin-19; D007633:Keratins; D008175:Lung Neoplasms / Q000175:diagnosis; D016066:Pleural Effusion, Malignant / Q000175:diagnosis*; D011863:Radioimmunoassay; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D053539:Keratin-19; C102012:antigen CYFRA21.1; D007633:Keratins