These findings from Vahteristo and coworkers [6] and recent work from Oldenburg and colleagues [7] are similar to data from the CHEK2 Breast Cancer Consortium, and suggest a significant role played by the 1100delC variant in breast cancer among women with a positive family history of breast cancer whose disease is not attributable to germline mutations in BRCA1 or BRCA2. Here, BRCA2 is linked to breast cancer.