BRCA1 and BRCA2 are genes that repair damage in cells and prevent them from growing and dividing too rapidly. All of us have two copies of these genes, but mutations in them can cause cells to become abnormal and grow in an uncontrolled way.
Having a mutation in one of these genes can increase a woman’s risk of both breast cancer and ovarian cancer. This can mean that a woman has an 80% chance of developing breast cancer in her lifetime and a 35-60% chance of developing ovarian cancer in her lifetime.
Those from Ashkenazi Jewish, Dutch, Icelandic, Norwegian, Pakistani, Polish and Swedish populations are more likely to have a BRCA1/2 gene mutation than some other populations.