BRCA2 and ductal breast carcinoma in situ: In another study of 655 DCIS patients, BRCA2 and CHEK2 mutations were the most prevalent, occurring at rates of 3.4% and 2.4%, with corresponding odds ratios of 27.96 (95% CI: 6.56–119.26) and 8.08 (95% CI: 2.93–22.05).