If breast cancer in the family, the risk of getting breast cancer also increased. When one first degree relative with breast cancer occurs (ie the mother, a sister or a daughter), a woman twice as likely that they will get breast cancer (ie approximately 20% chance instead of the usual 10% probability).
BRCA1 and BRCA2, two breast and ovarian cancer genes. It caused (only) 5 percent of breast cancers. A woman with a mutation in the gene has a 40-85 percent risk of getting the disease. When several women in one family at a younger age breast cancer, one can investigate mutations in these genes. This refers to the family doctor to the clinic by the Department of Clinical Genetics (in Belgium Center for Human Genetics) in a hospital. In case of a mutation in BRCA1 or BRCA2 is the preventive removal of the breasts an option.