title: Low values of 5-hydroxymethylcytosine (5hmC), the "sixth base," are associated with anaplasia in human brain tumors.
abstract: 5-Methylcytosine (5 mC) in genomic DNA has important epigenetic functions in embryonic development and tumor biology. 5-Hydroxymethylcytosine (5 hmC) is generated from 5 mC by the action of the TET (Ten-Eleven-Translocation) enzymes and may be an intermediate to further oxidation and finally demethylation of 5 mC. We have used immunohistochemistry (IHC) and isotope-based liquid chromatography mass spectrometry (LC-MS) to investigate the presence and distribution of 5 hmC in human brain and brain tumors. In the normal adult brain, IHC identified 61.5% 5 hmC positive cells in the cortex and 32.4% 5 hmC in white matter (WM) areas. In tumors, positive staining of cells ranged from 1.1% in glioblastomas (GBMs) (WHO Grade IV) to 8.9% in Grade I gliomas (pilocytic astrocytomas). In the normal adult human brain, LC-MS also showed highest values in cortical areas (1.17% 5 hmC/dG [deoxyguanosine]), in the cerebral WM we measured around 0.70% 5 hmC/dG. levels were related to tumor differentiation, ranging from lowest values of 0.078% 5 hmC/dG in GBMs (WHO Grade IV) to 0.24% 5 hmC/dG in WHO Grade II diffuse astrocytomas. 5 hmC measurements were unrelated to 5 mC values. We find that the number of 5 hmC positive cells and the amount of 5 hmC/dG in the genome that has been proposed to be related to pluripotency and lineage commitment in embryonic stem cells is also associated with brain tumor differentiation and anaplasia.
authors.affiliation: Center for Neuropathology and Prion Research, ZNP, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Theo F J
authors.initials: TF
authors.lastname: Kraus
authors.forename: Daniel
authors.initials: D
authors.lastname: Globisch
authors.forename: Mirko
authors.initials: M
authors.lastname: Wagner
authors.forename: Sabina
authors.initials: S
authors.lastname: Eigenbrod
authors.forename: David
authors.initials: D
authors.lastname: Widmann
authors.forename: Martin
authors.initials: M
authors.lastname: Münzel
authors.forename: Markus
authors.initials: M
authors.lastname: Müller
authors.forename: Toni
authors.initials: T
authors.lastname: Pfaffeneder
authors.forename: Benjamin
authors.initials: B
authors.lastname: Hackner
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Feiden
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schüller
authors.forename: Thomas
authors.initials: T
authors.lastname: Carell
authors.forename: Hans A
authors.initials: HA
authors.lastname: Kretzschmar
mesh_terms: D044503:5-Methylcytosine / Q000031:analogs & derivatives; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000708:Anaplasia; D001254:Astrocytoma / Q000235:genetics; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology*; D002540:Cerebral Cortex / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003596:Cytosine / Q000031:analogs & derivatives* / Q000032:analysis; D004247:DNA / Q000737:chemistry*; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D055815:Young Adult
chemical_list: C011865:5-hydroxymethylcytosine; D044503:5-Methylcytosine; D003596:Cytosine; D004247:DNA; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human