XRCC1 and adenoma: The combination of the XRCC1 codon 280 and XRCC1 codon 399 polymorphisms showed a significant positive association for carriers of the XRCC1 codon 280 variant allele and XRCC1 codon 399 wild type allele, in the high-risk adenomas only, OR of 2.92 (95 % CI 1.20–7.10).