We observed a wide variation of the Gln allele frequencies of control resources in Asians (0.27), Indians (0.35), Caucasians (0.35) and Africans (0.17), and this different allele frequency might account for the association between the XRCC1 Arg399Gln polymorphism and cancer susceptibility among different ethnicity. Here, XRCC1 is linked to cancer.