For further analysis we considered three subgroups in our total group of breast cancer patients: (1) a subgroup of patients that met criteria 1 and 2 (see Materials and Methods) and in which a mutation in BRCA1/2 was detected (BRCA1, n=4; BRCA2, n=7); (2) a subgroup of patients that met criteria 1 and 2 but without a mutation in BRCA1/2 (n=43); and (3) a group of young patients (age <35 year) without a family history and without a BRCA1/2 mutation (n=10). This evidence concerns the gene BRCA1 and breast cancer.