Polymorphisms in base excision repair genes: Breast cancer risk and individual radiosensitivity

Table 3 Association between X-ray repair cross-complementing group 1 single nucleotide polymorphisms and radiotherapy-induced side effects in breast cancer patients

Ref.	XRCC1 SNPs	Number of studies analysed	Result
Xie et al[38]	Arg399Gln	8	The 399Gln variant allele is associated with a higher risk of RT-induced toxicity (only in some subgroups of BC patients)
	Arg194Trp	6	No predictive value was found for this SNP
	-77 T > C	4	No predictive value was found for this SNP
	Arg280His	4	The 280His variant allele is protective against RT-induced toxicity (in BC patients treated with RT only)

XRCC1: X-ray repair cross-complementing group 1; SNP: Single nucleotide polymorphism; RT: Radiotherapy; BC: Breast cancer; Arg: Arginine; Gln: Glutamine; Trp: Tryptophan; His: Histidine; T: Thymine; C: Cytosine.