We analysed the prevalence of the following genetic polymorphisms XRCC1 (Arg399Gln) [rs25487], APEX1 (Asp148Glu) [rs1130409], XRCC3 (Thr241Met) [rs861539], XPD (Asp312Asn) [rs1799793] and (Lys751Gln) [rs13181], CYP1A1 (Ile462Val) [rs1048943], CYP2A6*2 (Lys160His) [rs1801272], and CYP2A6*9 (−48T > G) [rs28399433] in breast cancer patients and healthy smokers. The gene discussed is APEX1; the disease is breast cancer.