Genetic and Epigenetic Determinants of Response to Fluorouracil-based Adjuvant Chemotherapy in Patients With Stage III Colorectal Cancer

This is a prospective project in collecting and assessing clinical outcomes data related to molecular profiling of tumors based on samples from peripheral blood, primary tumor, and adjacent normal colorectal tissue. Objectives: 1. Validation of predictive value of known markers CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) in the response to 5-fluorouracil-based chemotherapy in patients with stage III colorectal cancer. 2. Exploratory evaluation of the potential predictive values of known genetic variations including, but not limited to, KRAS mutations, BRAF mutations, PIK3A mutations, and EGFR mutations, etc. 3. Exploratory identification and evaluation of the predictive value of novel methylation aberrations identified by whole-genome bisulfite sequencing. 4. Exploratory identification and evaluation of the predictive value of novel genetic aberrations discovered by RNA-sequencing (RNA-seq) or genome-wide association study (GWAS). Outline: Blood is collected at baseline and examined for single-nucleotide polymorphisms (SNPs) and expression level of specific gene. Tumor and corresponding normal tissue at surgical resection and assessed for gene methylations, mutations, and expressions.