Results suggest a gradual expansion of methylation across CpG islands in MGMT, RASSF2, and SFRP2 promoters during colorectal cancer progression and highlighted their potential role as biomarkers for diagnosis and disease prediction for specific cancer types (Nagasaka et al. 2008, 2009; Takeda et al. 2011). This evidence concerns the gene SFRP2 and colorectal cancer.