title: N-glycomic profiling as a tool to separate rectal adenomas from carcinomas.
abstract: All human cells are covered by glycans, the carbohydrate units of glycoproteins, glycolipids, and proteoglycans. Most glycans are localized to cell surfaces and participate in events essential for cell viability and function. Glycosylation evolves during carcinogenesis, and therefore carcinoma-related glycan structures are potential cancer biomarkers. Colorectal cancer is one of the world's three most common cancers, and its incidence is rising. Novel biomarkers are essential to identify patients for targeted and individualized therapy. We compared the N-glycan profiles of five rectal adenomas and 18 rectal carcinomas of different stages by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. Paraffin-embedded tumor samples were deparaffinized, and glycans were enzymatically released and purified. We found differences in glycosylation between adenomas and carcinomas: monoantennary, sialylated, pauci-mannose, and small high-mannose N-glycan structures were more common in carcinomas than in adenomas. We also found differences between stage I-II and stage III carcinomas. Based on these findings, we selected two glycan structures: pauci-mannose and sialyl Lewis a, for immunohistochemical analysis of their tissue expression in 220 colorectal cancer patients. In colorectal cancer, poor prognosis correlated with elevated expression of sialyl Lewis a, and in advanced colorectal cancer, poor prognosis correlated with elevated expression of pauci-mannose. In conclusion, by mass spectrometry we found several carcinoma related glycans, and we demonstrate a method of transforming these results into immunohistochemistry, a readily applicable method to study biomarker expression in patient samples.
authors.affiliation: From the ‡Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland; §Research Programs Unit, Translational Cancer Biology, University of Helsinki, Helsinki, Finland; tuomas.kaprio@helsinki.fi.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Kaprio
authors.affiliation: ¶Glykos Finland Ltd., Helsinki, Finland;
authors.forename: Tero
authors.initials: T
authors.lastname: Satomaa
authors.affiliation: ¶Glykos Finland Ltd., Helsinki, Finland;
authors.forename: Annamari
authors.initials: A
authors.lastname: Heiskanen
authors.affiliation: ‖Biomolecular Mass Spectrometry Unit, Department of Parasitology, Leiden University Medical Center, The Netherlands;
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Hokke
authors.affiliation: ‖Biomolecular Mass Spectrometry Unit, Department of Parasitology, Leiden University Medical Center, The Netherlands;
authors.forename: André M
authors.initials: AM
authors.lastname: Deelder
authors.affiliation: From the ‡Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland;
authors.forename: Harri
authors.initials: H
authors.lastname: Mustonen
authors.affiliation: **Department of Pathology, Haartman Institute, University of Helsinki and HUSLAB, Helsinki;
authors.forename: Jaana
authors.initials: J
authors.lastname: Hagström
authors.affiliation: ‡‡Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Olli
authors.initials: O
authors.lastname: Carpen
authors.affiliation: ¶Glykos Finland Ltd., Helsinki, Finland;
authors.forename: Juhani
authors.initials: J
authors.lastname: Saarinen
authors.affiliation: From the ‡Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland; §Research Programs Unit, Translational Cancer Biology, University of Helsinki, Helsinki, Finland;
authors.forename: Caj
authors.initials: C
authors.lastname: Haglund
mesh_terms: D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001216:Asparagine / Q000378:metabolism; D018395:CA-19-9 Antigen; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D054794:Glycomics / Q000379:methods*; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009844:Oligosaccharides / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D025341:Principal Component Analysis; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D016019:Survival Analysis
chemical_list: D018395:CA-19-9 Antigen; D009844:Oligosaccharides; D011134:Polysaccharides; D001216:Asparagine