The CHEK2 1100delC mutation has been found to double the risk of breast cancer in women.70 A meta-analysis found a cumulative risk of 37% before age 70 years in carriers of the mutation.71 However, the CHEK2 1100delC mutation was not found in Chinese women at high risk of breast cancer,72–75 or in other Asian populations.76 Liu et al75 screened the entire gene of CHEK2 and found that H371Y increased breast cancer risk (OR = 2.43, 95% CI = 1.07–5.52, P = 0.034). Here, CHEK2 is linked to breast cancer.