Changes in Serum IgG Oligosaccharide Chains with Prostate Cancer Progression

Abstract

Background: Changes of serum IgG oligosaccharide chain structure have been found in B cell lineage tumors and autoimmune diseases. Currently, the cancer-associated carbohydrate epitopes CA72-4 and CA15-3 are used as serum tumor markers. In the present study, we analyzed the structure of serum IgG oligosaccharide chains in prostate cancer (PCa) patients using the simple new method of fluorophore-associated carbohydrate electrophoresis (FACE). We also evaluated the relationship between changes of serum IgG oligosaccharide chain structure and serum concentration of prostate-specific antigen (PSA). Materials and Methods: The structure of serum IgG oligosaccharide chains from 12 PCa patients (6 localized cancer, 6 metastatic cancer) and 10 healthy controls was evaluated by FACE. PSA levels in serum were determined by enzyme immunoassay. Results: Fr 1 (monogalactosyl oligosaccharide) and Fr 2 (digalactosyl oligosaccharide) decreased significantly (p<0.05), while Fr 4 (agalactosyl IgG oligosaccharide) increased with PCa tumor progression. The Fr 4 / Fr 1+2 ratio in metastatic PCa patients was significantly higher than in healthy controls (p<0.05), and there was a significant correlation (r=0.84, p<0.05) between serum PSA levels and the Fr 4 / Fr 1+2 ratio in all patients with PCa. Conclusion: The changes of serum IgG oligosaccharide chain structure with PCa progression are based on the abnormality of glycosylation in PCa metastasis. Therefore, the analysis of serum IgG oligosaccharide chain structure by FACE may be an auxiliary indicator of PSA for monitoring PCa progression.