Heterozygous carriers of the NBN c.657del5 mutation (which is found in homozygous state in more than 90% of patients with Nijmegen breakage syndrome) who also carry two copies of the NBN polymorphism p.E185Q (GG allele) were shown to be at increased risk for breast and prostate cancers (204, 205). The gene discussed is NBN; the disease is prostate cancer.