title: Glycomic profiling of carcinoembryonic antigen isolated from human tumor tissue.
abstract: BACKGROUND
  Carcinoembryonic antigen (CEA) is a protein commonly found in human serum, with elevated CEA levels being linked to the progression of a wide range of tumors. It is currently used as a biomarker for malign tumors such as lung cancer and colorectal cancer [Urol Oncol: Semin Orig Invest 352: 644-648, 2013 and Lung Cancer 80: 45-49, 2013]. However, due to its low specificity in clinical applications, CEA can be used for monitoring only, rather than tumor diagnosis. The function of many glycoproteins is critically dependent on their glycosylation pattern, which in turn has the potential to serve in tumor detection. However, little is known about the detailed glycan patterns of CEA.
  
  
  METHODS
  To determine these patterns, we isolated and purified CEA proteins from human tumor tissues using immunoaffinity chromatography. The glycan patterns of CEA were then analyzed using a Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry(3) (MALDI-TOF-MS(3)) approach.
  
  
  RESULTS
  We identified 61 glycoforms in tumor tissue, where CEA is upregulated. These glycosylation entities were identified as bi-antennary, tri-antennary and tetra-antennary structures carrying sialic acid and fucose residues, and include a multitude of glycans previously not reported for CEA.
  
  
  CONCLUSIONS
  Our findings should facilitate a more precise tumor prediction than currently possible, ultimately resulting in improved tumor diagnosis and treatment.
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 P. R. China.
authors.forename: Chuncui
authors.initials: C
authors.lastname: Huang
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Colorectal Surgery, Peking University Cancer Hospital & Institute, No. 52 Fucheng Rd., Haidian District, Beijing, 100142 P. R. China.
authors.forename: Tiancheng
authors.initials: T
authors.lastname: Zhan
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 P. R. China.
authors.forename: Yaming
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 P. R. China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Li
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 P. R. China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Colorectal Surgery, Peking University Cancer Hospital & Institute, No. 52 Fucheng Rd., Haidian District, Beijing, 100142 P. R. China.
authors.forename: Dengbo
authors.initials: D
authors.lastname: Ji
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 P. R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
keywords: Carcinoembryonic antigen; Glycan profiling; MALDI-TOF-MS3