How are brca1 and brca2 related to the development of breast cancer?

BRCA 1 or 2: Breast cancer genes, brca1 or brca2. Resut in breast cancer development. About 5% of women with breast cancer carry a mutation in brca1 or 2 women with brca1 mutations also have a 20 to 40% lifetime risk of developing ovarian cancer; risk among women with brca2 mutations is increased less men who carry a brca2 mutation also have an increased risk of developing breast cancer the genes are more c.

Very high risk: Patients who are brca positive have a very high risk of developing breast cancer. They can have an 80-90% risk (over lifetime) of developing 1 breast cancer, 50-65% chance of developing a 2nd breast cancer and a 40-50% risk of developing ovarian cancer. Please see this link for more details: http://www.Cancer.Gov/cancertopics/factsheet/risk/brca.