DNA methylation signatures and the contribution of age-associated methylomic drift to carcinogenesis in early-onset colorectal cancer [article]

Jihoon E Joo, Mark Clendenning, Ee Ming Wong, Christophe Rosty, Khalid Mahmood, Peter Georgeson, Ingrid M Winship, Susan G Preseton, Aung Ko Unimelb, Pierre-antoine Dugue, Harindra Jayasekara, Dallas English (+7 others)
2021 medRxiv   pre-print
The role of DNA methylation (DNAm) in the carcinogenesis of colorectal cancer (CRC) diagnosed <50years of age (early-onset CRC or EOCRC) is currently unknown. We investigated aberrant DNAm changes and the contribution of ageing-associated methylomic drift, and age acceleration to EOCRC carcinogenesis. Methods: Genome-wide DNAm profiling using the Infinium HM450K on 97 EOCRC tumour and 54 normal colonic mucosa samples was compared with: 1) intermediate-onset CRC (IOCRC; diagnosed between 50-70
more » ... ars; 343 tumour and 35 normal); and 2) late-onset CRC (LOCRC; >70 years; 318 tumour and 40 normal). CpGs associated with age-related methylation drift were identified using a public dataset of 231 normal mucosa samples from people without CRC. DNAm-age was estimated using epiTOC2. Results: Common to all three age-of-onset groups, 88,385 (20% of all CpGs) CpGs were differentially methylated between tumour and normal mucosa. We identified 234 differentially methylated genes that were unique to the EOCRC group. In normal mucosa from people without CRC, we identified 28,154 CpGs that undergo ageing-related DNAm drift and of those, 65% were aberrantly methylated in EOCRC tumours. Based on the mitotic-based DNAm clock epiTOC2, we identified age acceleration in normal mucosa of people with EOCRC compared with normal mucosa from the IOCRC, LOCRC groups (p=3.7x10-16) and young people without CRC (p=5.8x10-6). Conclusion: EOCRC acquires unique DNAm alterations at 234 loci. CpGs associated with ageing-associated drift were widely affected in EOCRC without needing the decades-long accrual of DNAm drift as commonly seen in intermediate- and late-onset CRCs. We found accelerated ageing in normal mucosa from people with EOCRC, as evidenced by a faster stem-cell division rate, potentially contributing to EOCRC carcinogenesis.
doi:10.1101/2021.03.24.21254210 fatcat:esk5wvgz4naczimfqxfenmqwjy