Racial differences in epigenetic aging of the colon: Implications for colorectal cancer
Menée à partir de l'analyse du niveau de méthylation de l'ADN d'échantillons de tissus coliques de 128 personnes saines, cette étude examine, en fonction de l'origine ethnique (européenne ou africaine), la différence d'âge épigénétique entre le côlon droit et le côlon gauche
Epigenetic processes are implicated in field cancerization of the colorectum with global hypomethylation increasing sequentially in the stepwise progression of normal colorectal tissue to adenomas, adenocarcinomas, and metastatic disease.1–3The heritability of the epigenome4gradually decreases with age as potentially reversible epigenetic modifications capturing the cumulative tissue-specific response to a range of environmental exposures accrue.5–9With aging, there is an overall non-specific global hypomethylation concurrent with hypermethylation in specific gene regions. This has led to algorithms ofDNA methylation, such as the Horvath or Hannum clocks,which have emerged as the most accurate molecular markers of chronological age,10,11measured as calendar time since birth. Epigenetic algorithms also provide an estimate of age acceleration, a measure of an individual’s aging beyond chronological age. Recent iterations of epigenetic clocks estimate ‘biological aging’whichis associated with a higher risk of age-related conditions,such as cancers or cardiovascular disease,after accounting for chronological age. For example, PhenoAge12andGrimAge13clocks have been strongly associated with the risk of cancers, including colorectal, in a large cohort of participants of European ancestry.14However, there are limited data on the association of epigenetic markers with cancer risk among non-White individuals.
Journal of the National Cancer Institute , éditorial en libre accès, 2019