Serum Sialic Acid as a Marker of Pancreatic Cancers

Background: The carbohydrate alterations in sialoglycoproteins and sialoglycolipids cause the high serum concentration of sialic acid in many types of cancers. The aim of this study was to evaluate the diagnostic accuracy of total sialic acid (TSA), lipid-bound sialic acid (LSA), and free sialic acid (FSA) in patients with primary pancreatic cancers. Methods: TSA and LSA concentrations in the sera of 42 patients were measured by the enzymatic and FSA by the thiobarbituric method. Results: The mean levels of TSA, LSA, and FSA in the sera of patients with pancreatic cancers were significantly higher than in controls. Taking into consideration the size and the location of the tumors, regional lymph node and distant metastases, there were no differences in TSA, FSA, and CA 19-9 levels. However, the location of tumors in the pancreas affects LSA levels. The sialic acids, contrary to CA 19-9, are not useful tools in the differential diagnosis of tumors and non-malignant diseases of the pancreas. LSA has the highest sensitivity, negative predictive value, accuracy, and the ability to discriminate cancer patients from healthy controls. The diagnostic power of LSA is similar to CA 19-9. Conclusions: We suggest that LSA can be useful in the diagnosis and evaluation of the tumor location in patients with primary pancreatic cancers.