Specific Glycoforms of MUC5AC and Endorepellin Accurately Distinguish Mucinous from Nonmucinous Pancreatic Cysts

Abstract

Specific protein glycoforms may be uniquely informative about the pathological state of a cyst and may serve as accurate biomarkers. Here we tested that hypothesis using antibody-lectin sandwich arrays in broad screens of protein glycoforms and in targeted studies of candidate markers. We profiled 16 different glycoforms of proteins captured by 72 different antibodies in cyst fluid from mucinous and nonmucinous cysts (n ‫؍‬ 22), and we then tested a three-marker panel in 22 addition samples and 22 blinded samples. Glycan alterations were not widespread among the proteins and were mainly confined to MUC5AC and endorepellin. Specific glycoforms of these proteins, defined by reactivity with wheat germ agglutinin and a blood group H 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 nonmucinous cysts with 93% accuracy (89% sensitivity, 100% specificity) in a prevalidation 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 wheat germ agglutinin and blood group H reactivity was due to oligosaccharides terminating in GlcNAc or N-acetyl-lactosamine with occasional ␣1,2-linked fucose. The results show that MUC5AC and endorepellin glycoforms may be highly specific and sensitive biomarkers for the differentiation of mucinous from nonmucinous pancreatic cysts. Molecular & Cellular

Characterization of Glycoproteins in Pancreatic Cyst Fluid Using a High-Performance Multiple Lectin Affinity Chromatography Platform

“…9-11 Investigating and analyzing glycoproteins of pancreatic cyst fluid represents a potentially valuable source for information and can benefit in differentiating mucinous from non-mucinous cysts. In glycoproteomics, specific glycoproteins and glyco-isoforms are enriched followed by matrix assisted laser desorption or liquid chromatography mass spectrometry analysis.…”

Endosonography in the diagnosis and management of pancreatic cysts

“…A recent study of the cyst fluid proteome demonstrated that proteomic profiling of mucin in cyst fluid (obtained by EUS-FNA) was 98% accurate for pre-malignant and malignant cysts [64] . A study of select proteins in 22 cyst fluid samples identified a 3 biomarker panel of protein glycoforms that was 91% accurate for mucinous cysts [65] . Metabolomic analysis has demonstrated that metabolites, glucose and kynurenine, were lower in mucinous cysts compared to non-mucinous cysts [66] .…”

Endostatin and endorepellin: A common route of action for similar angiostatic cancer avengers

“…Endorepellin has been also identified in the fetal bovine rib growth plate [196], and in proteomic studies of chronic allograft nephropathy [197]. More recently, full-length endorepellin has been identified in pancreatic cysts [198]. …”