Recent studies indicate thataround 50% of families with mutations identified in BRCA1/BRCA2 do nothave close relatives with breast cancer or ovarian cancer (due mainly to small familysize or limited family structure) and, as a consequence, do not fulfill clinicalcriteria for hereditary breast cancer predisposition syndrome or for genetic testing(Weitzel et al., 2007). This evidence concerns the gene BRCA1 and breast cancer.