In a study of stage II/III rectal cancer patients in Spain, patients with XRCC1 Arg/Arg had a greater probability of a positive response to chemoradiotherapy than those with XRCC1 Arg/Gln (OR  = 4.18, 95% CI  = 1.62–10.7) [35]. Here, XRCC1 is linked to rectal cancer.