Genome-wide DNA methylation profiling of colorectal tumours from MLH1 epimutation carriers

Genome-wide DNA methylation analysis of colorectal tumour samples from 44 FFPE tumour and 15 FFPE normal mucosa samples was performed to invesgitate genome-wide DNA methylation signatures that can distinguish MLH1 epimutation carrier CRCs. This was further applied to resolve clinically challenging CRCs including MLH1 promoter VUS carriers and MLH1 methylated EOCRCs Genomic DNA derived from 44 FFPE tumour samples and 15 FFPE normal mucosa samples was bisulfite converted and hybridised to the Illumina Infinium EPIC human methylation beadchips. The methylation data was preprocessed using minfi Bioconductor package and underwent Functional normalisation. Probes with detection P >0.05 were removed. Beta values were calculated using minfi.