Evaluation of epigenetic methylation biomarkers for the detection of colorectal cancer using droplet digital PCR

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide. Screening programs allow early diagnosis and have improved the clinical management of this disease. Aberrant DNA methylation is increasingly being explored as potential biomarkers for many types of cancers. In this study we investigate the methylation of ten target genes in 105 CRC and paired normal adjacent tissue samples using a MethylLight droplet digital PCR (ML-ddPCR) assay. Receiver operator characteristic (ROC) curves were used to determine the diagnostic performance of all target genes individually and in combination. All 515 different combinations of genes showed significantly higher levels of methylation in CRC tissue. The combination of multiple target genes into a single test generally resulted in greater diagnostic accuracy when compared to single target genes. Our data indicates that aberrant DNA methylation in a specific selection of target genes illustrates very strong potential for use as a screening marker for CRC.

Ultrasensitive amplification-free quantification of a methyl CpG-rich cancer biomarker by single-molecule kinetic fingerprinting

“…The target sequence comprises 13 CpG sites (only nine of which are detected and thus shown in Fig. 1 ) whose hypermethylation is linked to colorectal cancer 8, 9, 11, 13, 14, 38 . The assay starts with bisulfite treatment to convert unmethylated cytosines in the double-stranded DNA (dsDNA) target to uracils as shown in Fig.…”