Evaluation of Cyfra 21-1: a potential tumor marker for non-small cell lung carcinomas

Cyfra 21-1 is a tumor marker based on the determination of water-soluble cytokeratin 19 which is secreted by normal or malignantly transformed epithelial cells. It is suggested to be a valuable marker in patients with non-small cell lung carcinoma (NSCLC). A prospective clinical study was conducted to investigate the value of Cyfra 21-1 for diagnosis, determination of subtypes, staging, and evaluation of therapy response in patients with lung carcinoma (Ca). Sixty-nine patients (mean age: 60.9 +/- 9.2 years, M/F:12.8) treated between 1994 and 1998 inclusive, and 13 healthy smokers (mean age:50.9 +/- 4.8 years, M/F:1.6) constituted the study group and control group, respectively. Venous blood samples (10 ml) were obtained from all subjects. Posttreatment blood samples were also obtained from 14 NSCLC patients. Cyfra 21-1 levels (cutoff value 3.3 ng/ml) were determined by ELSA-Cyfra 21-1 kit (CIS bio international, France) through immunoradiometric assay (IRMA). Cyfra 21-1 levels did not differ between smoking and non-smoking subjects within each group (p > 0.05). Cyfra 21-1 was significantly elevated in lung Ca cases irrespective of the cell type (p < 0.05). It was significantly elevated in squamous cell and adenocarcinoma varieties with the most prominent elevation in squamous cell type (p < 0.05). In lung Ca, the specificity and sensitivity of Cyfra 21-1 was 92.3% and 52.2%, respectively. Sensitivity was 65.5% for NSCLC, 70.5% for squamous cell, and 45.5% for adenocarcinoma varieties, with highest sensitivity rates in Stage IIIA + IIIB (87.5%) and Stage IV (75%) of squamous cell lung Ca. Cyfra 21-1 level was significantly decreased after treatment in NSCLC patients (n 14) (p < 0.01). Cyfra 21-1 is a tumor marker that helps to establish the diagnosis and differentiation of cell type and evaluation of response to therapy in patients with NSCLC.