title: Glyco-genes change expression in cancer through aberrant methylation.
abstract: BACKGROUND
  Most eukaryotic proteins are modified by covalent addition of glycan molecules that considerably influence their function. Aberrant glycosylation is profoundly involved in malignant transformation, tumor progression and metastasis. Some glycan structures are tumor-specific and reflect disturbed glycan biosynthesis pathways.
  
  
  METHODS
  We analyzed DNA methylation and expression of 86 glyco-genes in melanoma, hepatocellular, breast and cervical cancers using data from publicly available databases. We also analyzed methylation datasets without the available matching expression data for glyco-genes in lung cancer, and progression of melanoma into lymph node and brain metastases.
  
  
  RESULTS
  Ten glyco-genes (GALNT3, GALNT6, GALNT7, GALNT14, MGAT3, MAN1A1, MAN1C1, ST3GAL2, ST6GAL1, ST8SIA3) showing changes in both methylation and expression in the same type of cancer belong to GalNAc transferases, GlcNAc transferases, mannosidases and sialyltransferases, which is in line with changes in glycan structures already reported in the same type of tumors. Some of those genes were additionally identified as potentially valuable for disease prognosis. The MGAT5B gene, so far identified as specifically expressed in brain, emerged as a novel candidate gene that is epigenetically dysregulated in different cancers other than brain cancer. We also report for the first time aberrant expression of the GALNT and MAN genes in cancer by aberrant promoter methylation.
  
  
  CONCLUSIONS
  Aberrant expression of glyco-genes due to aberrant promoter methylation could be a way leading to characteristic glycosylation profiles commonly described in cancer.
  
  
  CONCLUSIONS
  Methylation status in promoters of candidate glyco-genes might serve as prognostic markers for specific tumors and point to potential novel targets for epigenetic drugs. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
authors.affiliation: University of Zagreb Faculty of Science, Department of Biology, Division of Molecular Biology, Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Vojta
authors.affiliation: University of Zagreb Faculty of Science, Department of Biology, Division of Molecular Biology, Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Samaržija
authors.affiliation: University of Zagreb Faculty of Science, Department of Biology, Division of Molecular Biology, Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Luka
authors.initials: L
authors.lastname: Bočkor
authors.affiliation: University of Zagreb Faculty of Science, Department of Biology, Division of Molecular Biology, Horvatovac 102a, HR-10000 Zagreb, Croatia. Electronic address: vzoldos@biol.pmf.hr.
authors.forename: Vlatka
authors.initials: V
authors.lastname: Zoldoš
mesh_terms: D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D030541:Databases, Genetic; D044127:Epigenesis, Genetic; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009369:Neoplasms / Q000201:enzymology / Q000235:genetics; D011401:Promoter Regions, Genetic
chemical_list: D004273:DNA, Neoplasm; D009363:Neoplasm Proteins
keywords: Cancer; DNA methylation; Epigenetics; Gene expression; Protein glycosylation