Epigenetic reduction of DNA repair in progression to gastrointestinal cancer

Table 4 CpG island hyper- (and hypo-) methylation of DNA repair genes in cancers

Cancer	Gene	Frequency of promoter hyper-(or hypo-) methylation in cancer
Colorectal	LIG4	82%[78]
	MGMT	40%-90%[17-21]
	ERCC1	38%[79]
	WRN	29%-38%[63,80]
	MLH1	9%-10%[22,81]
	FEN1	Frequent (hypo-)[82]
	MBD4	Frequent (hyper-)[61]
Esophageal	MGMT	23%-79%[65,83,84]
	MLH1	43%[82], 64%[85]
	MSH2	29%[83], 75%[84]
Stomach	MGMT	88%[60]
	MLH1	73%[64]
	WRN	24%-25%[80,86]
	FEN1	Frequent (hypo-)[82]
Gastric lymphoma	ATM	11%[87]