All women are at risk for developing breast cancer. However, there are certain factors that may increase a woman's chance of getting the disease. These include:

Age: The number one risk factor for developing breast cancer is age. Risk increases as a woman ages. Three out of four breast cancers occur in women over age 50, and the risk is highest for women over age 60.

Race: Breast cancer occurs more often in Caucasian women than African American or Asian women.

Personal History: Women who had breast cancer face an increased risk of developing breast cancer in the other breast.

Genetic Inheritance:  A woman is at greater risk if her mother, sister or daughter had breast cancer, particularly before menopause. Also, risk is higher if two or more other close relatives, such as aunts or cousins, have a history of breast cancer, especially at a young age. About 5 to 10 percent of women with breast cancer have a hereditary form of the disease. Some individuals of Ashkenazi (Eastern European) Jewish decent have been found to have an inherited characteristic that may increase their risk of developing breast or ovarian cancer.

Breast Changes: Women with a diagnosis of atypical hyperplasia (no cancerous condition in which cells have abnormal features and are increased in number) or lobular carcinoma in situ (abnormal cells found in the lobules of the breast), or having had two or more breast biopsies for other benign conditions are at increased risk for developing breast cancer.

Childbearing: Women having their first child after age 30 and women having no children have a greater risk than those having a first child at an earlier age.

Estrogen: Increased length of exposure to estrogen influences risk. This includes women who began menstrual periods at an early age, entered menopause at a late age, or women who take hormone replacement therapy for an extended period of time.

Breast Density: Cancer is more likely to occur in breasts with greater dense tissue, than in breasts with greater fatty tissue. Also, dense, glandular breasts make identifying abnormalities on a mammogram more difficult.

Radiation Therapy: Women whose breasts were exposed to radiation therapy before age 30, especially those treated with radiation for Hodgkin's disease, are at increased risk for breast cancer.

Lifestyle Factors: Some studies suggest that certain lifestyle behaviors can put women at greater risk for developing breast cancer. These include alcohol consumption; lack of exercise and weight gain, particularly in postmenopausal women; and working at night under artificial lighting.

Most women who develop breast cancer have none of the risk factors listed above, other than the risk that comes with growing older.