Abstract 3313: Epigenetic biomarkers of prognosis in stage IIA colon cancer

Adjuvant therapy is a systemic treatment administered after primary tumor resection to reduce the risk of relapse and death in colorectal cancer (CRC) patients. Generally, adjuvant treatment is recommended for stage III and ‘high-risk' stage II CRC (NCCN guidelines). Nonetheless, adjuvant treatment is still debated for stage IIA (T3N0) patients, whose estimated recurrence rate is 15-20% in the absence of any further therapy after resection of the primary tumor. With the aim to find additional prognostic biomarkers that could improve current patient selection, we analyzed the global methylation profile of a discovery group of 10 relapsing/non-relapsing stage IIA colon cancer samples, without any other known risk factor (low-risk), by Illumina Epic 850K array. We identified a panel of 25 Illumina probes that were able to predict recurrence in chemotherapy-naïve patients. Then, we assessed the methylation of the most predictive Cytosine-Guanine (CpG) dinucleotides in 107 stage IIA colon cancer patients from two different cohorts, by EpiTYPER technology. We validated several CpGs as differentially methylated in relapsing vs. non-relapsing CRCs (p