Newer evidence found that the complex interaction of high serum levels of PCBs and a particular variant (exon 7) of the CYP1A1 gene was associated with an increased risk for breast cancer (HR = 2.78; 95% CI = 0.99–7.82, compared to women with lower PCB levels and the wild-type genotype) [486]. The gene discussed is CYP1A1; the disease is breast carcinoma.