XRCC2 and XRCC3 polymorphisms are not associated with risk of colorectal adenoma.

The XRCC2 and XRCC3 proteins participate in homologous recombination and DNA double-strand break repair to maintain chromosomal stability. Coding-region variants in XRCC2 (Arg188His) and XRCC3 (Thr241Met) have been associated with cancers at several sites (1-3). The XRCC3 241Met homozygous variant has also been associated with increased DNA adduct levels, suggesting a role for this protein in repairing DNA adducts (2). We assessed the association between XRCC2 R188H, XRCC3 T241M, and two intronic XRCC3 polymorphisms and risk of colorectal adenoma in two case-control studies nested in the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS) cohorts. We hypothesize that XRCC2 and XRCC3 polymorphisms modify risk of colorectal adenoma associated with smoking and alcohol intake; both established risk factors for colorectal adenoma (4). In addition, we examine the XRCC2 and XRCC3 polymorphisms and their potential interaction with plasma and dietary folate in relation to risk of colorectal adenoma.