. Author manuscript; available in PMC: 2015 Mar 1.

Published in final edited form as: Future Oncol. 2014 May;10(7):1215–1237. doi: 10.2217/fon.14.60

Table 1.

Overlap and crosstalk among DNA repair pathways.

Pathway	Backup	Type of problem/provision for repair
DR	MMR	If MGMT fails to remove O⁶-methylguanine, the MMR pathway can recognize and fix O⁶-methylguanine misspairs
	MMR	MMR can repair postreplicative guanine/thymine mismatches Futile MMR cycles create DSBs, which either induces apoptosis or activate repair by HR or NHEJ
	NER	NER can repair larger adducts at the O⁶ position of guaninethat MGMT cannot repair
	BER	BER can repair mismatch pairs and other alkylation adducts that DR does not repair

BER	NER	NER can serve as a backup for repairing minor oxidative damage
	HR	If BER does not repair ssDNA breaks, they may lead to DSBs, which HR can repair
	HR/NHEJ	If BER fails to repair SSBs, HRcan repair them during replication (S phase). If signaling arrests the cell cycle at G1, then NHEJ can repair the breaks

NHEJ	HR	HR can repair DNA DSBs that the NHEJ pathway fails to process

BER: Base excision repair; DR: Direct repair; DSB: Double-stranded break; HR: Honnologous reconnbination; MMR: Misnnatch repair; NER: Nucleotide excision repair; NHEJ: Nonhonnologous end joining.

Data taken from [6].