BRCA1 and breast cancer: In a second report conducted in 780 patients with sporadic breast cancer (no criteria for family breast cancer), the six founder mutations previously described were studied and it was found that mutations A1708E and 3450delCAAG in BRCA1 were positive in 2.9% and mutation 3034delACAA in BRCA2 was positive in 1.3% of the patients .20