title: Evaluation of a potential epigenetic biomarker by quantitative methyl-single nucleotide polymorphism analysis.
abstract: Tumorigenesis is characterized by alterations of methylation profiles including loss and gain of 5-methylcytosine. Recently, we identified a single CpG, which seemed to be consistently hypomethylated in pilocytic astrocytomas but not in other gliomas. To evaluate its applicability as a biomarker, we examined its methylation status in a large panel of gliomas (n = 97). Methylation-dependent DNA sequence variation may be considered a kind of single nucleotide polymorphism (methylSNP). MethylSNPs can be easily converted into common SNPs of the C/T type by sodium bisulfite treatment of the DNA and afterwards subjected to conventional SNP typing. We adapted SnaPshot trade mark and Pyrosequencing trade mark to determine the methylation of our test CpG in a quantitative manner. The adapted methods, called SNaPmeth and PyroMeth, respectively, gave nearly identical results, however data obtained with PyroMeth showed less scattering. Furthermore, the integrated software for allele frequency determination from Pyrosequencing could be used directly for data analysis while SnaPmeth data had to be exported and processed manually. Although data did not confirm our previous result of a preferential hypomethylation of the tested CpG in pilocytic astrocytomas, we consider quantitative methylSNP analysis by SNaPmeth or PyroMeth a favorable alternative to existing high-throughput methylation assays. It combines single CpG analysis with accurate quantitation and is amenable to high throughput.
authors.affiliation: Gene Mapping Center, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Uhlmann
authors.forename: Anja
authors.initials: A
authors.lastname: Brinckmann
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Toliat
authors.forename: Heide
authors.initials: H
authors.lastname: Ritter
authors.forename: Peter
authors.initials: P
authors.lastname: Nürnberg
mesh_terms: D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000235:genetics* / Q000473:pathology; D001483:Base Sequence; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D019175:DNA Methylation; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000235:genetics* / Q000302:isolation & purification; D015226:Dinucleoside Phosphates / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D005260:Female; D005819:Genetic Markers; D005910:Glioma / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000235:genetics / Q000473:pathology; D016133:Polymerase Chain Reaction / Q000379:methods; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D017931:DNA Primers; D004273:DNA, Neoplasm; D015226:Dinucleoside Phosphates; D005819:Genetic Markers; C015772:CpG dinucleotide