Cyfra 21-1 as a marker of lung cancer

The utility of cytokeratin fragment (Cyfra) 21-1, a new tumor marker, was investigated in 100 patients with lung cancer. Sandwich enzyme immunoassay detected Cyfra 21-1 in the sera of 60% of patients. Sensitivity of this marker was especially high (86.4%) for squamous cell carcinoma, exceeding that of a similar marker, squamous cell carcinoma antigen (SCC, 54.5%). In contrast, sensitivity of Cyfra 21-1 was relatively low for adenocarcinoma (52.6%) and for small cell carcinoma (50%). We conclude that Cyfra 21-1 is of value in diagnosis of lung cancer, particularly squamous cell carcinoma.