Genome-wide DNA methylation analysis of colorectal adenomas with and without recurrence reveals an association between CpG methylation and histological subtypes.
Ontology highlight
ABSTRACT: Aberrant methylation of DNA is supposed to be a major and early driver of colonic adenoma development and may also lead to colorectal cancer (CRC) formation. While gene methylation assays are used already for CRC screening, differential epigenetic alterations of recurring and non-recurring colorectal adenomas have yet not been systematically investigated. Here, we collected a sample set (n=72) of formalin-fixed paraffin-embedded (FFPE) primary colorectal adenomas without recurrence (n=30), primary adenomas with recurrence at the same location (n=19), so-called “matched pair samples” (n=10; comprising the primary adenoma and the recurrent adenoma) and normal mucosa specimens (n=3). We aimed to unveil differentially methylated CpG positions (DMPs) across the methylome of the selected samples using the Illumina HumanMethylation 450K BeadChip array. Unsupervised hierarchical clustering exhibited a significant association of methylation patterns with the histological subtypes. No significant DMPs were identified comparing primary adenomas with and without recurrence. Despite that, a total of 5,094 DMPs (FDR<0.05, fold change>10%) were identified in the comparisons of recurrent adenomas vs. (non-) matched primary adenomas with recurrence (674; 98% hypermethylated), recurrent adenomas vs. primary adenomas with and without recurrence (241; 99% hypermethylated) and adenomas vs. normal mucosae (4,179; 46% hypermethylated). DMPs in CpG islands were frequently hypermethylated whereas open sea and shelves exhibited hypomethylation. Gene ontological analysis demonstrated enrichment of genes associated with the immune system, inflammatory processes, and cancer-pathways. We conclude that methylation data is helpful to contribute to a more stable and reproducible histological adenoma classification which is a prerequisite to establishing profound surveillance guidelines
ORGANISM(S): Homo sapiens
PROVIDER: GSE129364 | GEO | 2019/06/01
REPOSITORIES: GEO
ACCESS DATA