Association of CHFR Promoter Methylation with Disease Recurrence in Locally Advanced Colon Cancer

Abstract

This study was designed to determine whether DNA methylation biomarkers are associated with recurrence and survival in colon cancer patients. A retrospective analysis of 82 patients who received curative surgical resection for American Joint Committee on Cancer (AJCC) high-risk stage II or III colon cancer (1999-2007) was conducted. DNA methylation status was quantitatively evaluated by the pyrosequencing method. We preselected three tumor suppressor genes and one locus of interest; CHFR, ID4, RECK, and MINT1. Mean methylation levels of multiple CpG sites in the promoter regions were used for analysis; 15% or more was defined as methylation positive. The association of recurrence-free survival (RFS) and overall survival (OS) with methylation status was analyzed by the log-rank test, Kaplan-Meier method, and Cox proportional hazards model. Methylation levels of ID4, MINT1, and RECK did not correlate with RFS or OS. CHFR was methylation positive in 63% patients. When methylation status was dichotomized (negative or low: <30%, high: ≥30%), patients with CHFR methylation-high (44%) had worse RFS (P = 0.006) and reduced OS (P = 0.069). When stratified by stage, CHFR methylation-high was associated with reduced RFS (P = 0.004) and OS (P = 0.010) in stage III patients. CHFR methylation-high was commonly associated with N2 disease (P = 0.04) and proximal tumors (P = 0.002). Multivariate analysis indicated AJCC T4 disease and CHFR methylation-high (P = 0.001 and P = 0.015, respectively) were independent predictors for recurrence. The extent of CHFR promoter methylation correlates with RFS, indicating it is a promising epigenetic marker for recurrence.