Review Article

Genetics, Cytogenetics, and Epigenetics of Colorectal Cancer

Table 5

Genetics and environmental factors linked to epigenetic changes in CRC.

Genetic and environmental factorsEpigenetic changes in CRC

TYMS 28 bp 3R/3R genotypeAssociated with CIMP−CRC
MTHFR 677TT + 1298 CC genotypes/adequate folate intakeReduced MSI CRC risk
MTHFR AC or CC genotype, low folate and methionine, high alcholAssociated with CIMP+ CRC risk
TCNII 776G variantReduced CIMP+ CRC risk
MTHFR 677CT genotypeDecreased MGMT promoter hypermethylation
MTR A2756G Reduced CIMP CRC risk, among men
MTRR A66GReduced MLH1 methylation
DNMT -149TTReduced risk proximal CRC (principally CIMP+ tumour)
High serum folate/vitB12Associated with P16 promoter methylation and with MLH1, MLH2 promoter methylation(trend)
Choline deficiencyReduced CDKN3 promoter methylation
Low folate/High alcoholIncreased APC 1A, P14, MLH1, MGMT, and RASSF1A promoter methylation (trend)
Alchol (murine studies)Reduced MTR levels/DNA hypomethylation
TobaccoReduced methylation levels of MGMT, RAR-b, and SST genes
Heavy smokers/low folate/low fiber intake/long-term alcohol consumptionIncreased CIMP+ CRC risk (trend)
Green teaDemethylation of MLH1, MGMT, and P16 genes
Energy restrictionDecreased CIMP+ CRC
Higher dietary fiberReduced risk CIMP+ CRC/restore protein acetylation (p53, Sp1, Sp3)
ObesityIncreased CIMP-low CRC, not CIMP high CRC
Physical activity/use NSAIDsReduced CIMP-low and CIMP-high CRC