the precise causes of breast cancer are unclear, we know the main risk factors.
Still, most women considered at high risk for breast cancer do not get it,
while many with no known risk factors do develop breast cancer. Among the most
significant factors are advancing age and a family history of breast cancer.
Risk increases for a woman who has certain types of benign breast lumps and
increases significantly for a woman who has previously had cancer of the breast
or the ovaries.
A woman whose mother, sister, or daughter has had breast cancer is two to three
times more likely to develop the disease, particularly if more than one
first-degree relative has been affected. Researchers have identified two genes
responsible for some instances of familial breast cancer. These genes are known
as BRCA1 and BRCA2. About one woman in 200 carries the genes. Having one of
them predisposes a woman to breast cancer but does not ensure that she will get
Generally, women over age 50 are more likely to get breast cancer than younger
women, and African-American women are more likely than Caucasians to get breast
cancer before menopause