Sialic Acid Linkage Analysis Refines the Diagnosis of Ovarian Cancer

Discussion In the present study, we focused on the analysis of sialic acid linkages from primary serous ovarian cancer patients in early (FIGO I + II) and late stages (FIGO III + IV) of the disease to age-matched healthy controls. N-Glycans from serum samples were released by PNGase F and sialic acids were stabilized by linkage-specific labeling (18) before MALDI-TOF-MS measurement. High-mannose and neutral complex-type N-glycan structures showed statistically significant differences only between healthy patients and late stage ovarian cancer patients and no differences between healthy controls and early stage patients. Additionally, increases of antennarity were observed here that correspond with the published literature, since increased expression of GlcNAcT IV and V leads to increased branching and thus antennarity (21, 22). Interestingly, in this study, N4H3F1, the agalactosylated N-glycan present on IgG (23), the most abundant serum glycoprotein, did not show any statistical difference whereas its galactosylated forms N4H4F1 and N4H5F1 were significantly decreased. Saldova and colleagues (15) showed using ovarian cancer samples, irrespective of FIGO stages, that there was a decrease of IgG galactosylation and an increase of agalactosyl IgG N-glycans in ovarian cancer patients. However, it should be noted that our analysis was performed on 110 whole serum N-glycome samples and not at the IgG level alone. This is the reason why the observed changes can only be p...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research