Authors:
Zheng Cao, Kevin Maupin, Bryan Curnutte, Brian Fallon, Christa L. Feasley, Elizabeth Brouhard, Richard Kwon, Christopher M. West, John Cunningham, Randall Brand, Paola Castelli, Stefano Crippa, Ziding Feng, Peter Allen, Diane M. Simeone, and Brian B. Haab
Summary:
Purpose - Previously we have shown that specific protein glycoforms may be uniquely informative about the pathological state of a cyst and may serve as accurate biomarkers. Here we tested this hypothesis using antibody-lectin sandwich arrays in broad screens of protein glycoforms and in targeted studies of candidate markers.
Experimental design - We profiled 16 different glycoforms of proteins captured by 72 different antibodies in cyst fluid from mucinous and non-mucinous cysts (n = 22), and we then tested a three marker panel in 22 addition samples and 22 blinded samples.
Results - Glycan alterations were not widespread among the proteins but were mainly confined to MUC5AC and endorepellin. Specific glycoforms of these proteins, defined by reactivity with wheat-germ agglutinin (WGA) and a blood group H (BGH) antibody, were significantly elevated in mucinous cysts, whereas the core protein levels were not significantly elevated. A three-marker panel based on these glycoforms distinguished mucinous from non-mucinous cysts with 93% accuracy (89% sensitivity, 100% specificity) in a pre-validation sample set (n = 44) and with 91% accuracy (87% sensitivity, 100% specificity) in independent, blinded samples (n = 22). Targeted lectin measurements and mass spectrometry analyses indicated that the higher WGA and BGH reactivity was due to oligosaccharides terminating in GlcNAc or N-acetyl-lactosamine with occasional α1,2-linked fucose.
Conclusions - MUC5AC and endorepellin glycoforms may be highly specific and sensitive biomarkers for the differentiation of mucinous from non-mucinous pancreatic cysts.
Source:
Molecular & Cellular Proteomics; (07/08/13)