The colon cancer risk increases exponentially with age, and older age and inadequate folate intake are strongly implicated as important risk factors for colon cancer.32 The effects of aging and dietary folate on specific features of DNA methylation in the colon of mice have been studied by Keyes et al.33 Aging decreased genomic DNA methylation and increased promoter methylation and expression of CDKN2a. This evidence concerns the gene CDKN2A and colonic neoplasm.