Comparative study of CA-50 (time-resolved fluoroimmunoassay), Span-1, and CA19-9 in the diagnosis of pancreatic cancer.

The clinical diagnostic utility of CA-50 (time-resolved fluoroimmunoassay) and Span-1 was compared with that of CA19-9 by measuring their levels in sera from patients with pancreatic cancer and other diseases. In pancreatic cancer CA-50, Span-1, and CA19-9 showed similar positive rates (84%, 82%, and 81%, respectively). With regard to the ability to distinguish pancreatic cancer from chronic pancreatitis, however, the specificity of CA-50 and Span-1 was higher than that of CA19-9 (85%, 85%, and 79%, respectively). Despite the similar positive rates of CA-50 and Span-1 in pancreatic cancer, the correlation between these two markers was low. Thus, used in combination, they compensated for each other in the diagnosis of pancreatic cancer. In chronic liver diseases, serum levels of both CA-50 and Span-1 were correlated with that of biliary tract enzymes, alkaline phosphatase, and r-glutamyl transpeptidase. And these two markers were more affected by the biliary system than CA19-9, resulting in the significantly higher positive rates. In these diseases immunohistochemical study showed that all three markers were localized in the epithelial cells of the bile duct, with CA-50 and Span-1 showing a similar tissue distribution.