Clinical significance of serum CYFRA 21-1 in gastric cancer.

We studied the clinical significance of the soluble cytokeratin 19 fragment detected with monoclonal antibody CYFRA 21-1 in the sera of patients with histologically proven gastric cancer. Sera of 110 patients with gastric cancer were analysed for CYFRA 21-1 levels by a two-step sandwich enzyme immunoassay. There were no significant differences between CYFRA 21-1 levels and the histotype, depth of invasion or vessel invasion. However, CYFRA 21-1 was significantly higher in the presence of peritoneal metastases, liver metastases and extensive nodal involvement. When the positive cut-off value was defined as 5 ng ml-1, the CYFRA 21-1 in the stage IV and recurrent cases was 55.6% and 66.7%, respectively, which was as high as carcinoembryonic antigen (CEA) and greater than carbohydrate antigen 19-9 (CA 19-9). The positivities in stage I/II and III were zero and 5.9%, respectively, and false-positive rate in 76 patients with benign gastrointestinal disorders was 2.6%. There appeared to be no correlation between CYFRA 21-1 and CEA or CA 19-9. The patients with above 5 n ml-1 of CYFRA 21-1 had a significantly poorer prognosis. Multivariate analysis indicated that CYFRA 21-1 was an independent prognostic factor, while CEA and CA 19-9 failed to be of prognostic value. In conclusion, CYFRA 21-1 is a reliable tumour marker for gastic cancer in predicting very advanced cases, recurrence of the disease and overall poor prognosis.