Personal history of breast cancer: If you have had breast cancer already, you are at risk of it coming back. That risk might be low or high, depending on your situation. And you are at higher risk of getting a NEW breast cancer compared to someone else who has never had the disease.

Family history: Breast cancer in your family can have a significant impact on your risk. But this doesn't ALWAYS mean that you are at high risk just because someone in your family had breast cancer. For example, if your grandmother was diagnosed with breast cancer at age 75, this may not increase your risk of the disease. Your grandmother was most likely just 1 of the 13 women who gets breast cancer between the ages of 60 and 79.

Certain breast changes: Normal breast cells can sometimes get overexcited and start to misbehave. These changes can show up as a lump, thickness, or calcifications on a mammogram. If a biopsy is done, these changes can be seen under a microscope. When the breast duct cells are overactive and appear unusual, the pathology report may describe these findings with the term atypical ductal hyperplasia . An uncontrolled growth of breast cells in the lobule (the part of the breast that makes milk) is called lobular carcinoma in situ or LCIS . (Even though the word “carcinoma” is part of the term LCIS, it is not considered a true cancer.). These two types of breast changes are associated with an increased risk of breast cancer in the future. But these abnormalities are not themselves cancerous.

Genetic alterations : To date, most inherited cases of breast cancer have been associated with two genes: BRCA1, which stands for BR east CA ncer gene one, and BRCA2, or BR east CA ncer gene two. The function of these genes is to keep breast cells growing normally and to prevent any cancer cell growth. But when these genes contain abnormalities, or mutations, they are associated with an increased breast cancer risk. Abnormal BRCA1 and BRCA2 genes may account for up to 10% of all breast cancers. Women diagnosed with breast cancer who have an abnormal BRCA1 or BRCA2 gene often have a family history of breast cancer, ovarian cancer, or both. There are also women with a strong family history of breast cancer who might have another kind of genetic abnormality that's not yet been identified. But it's also important to remember that most women with breast cancer have no significant family history of the disease.

Menstrual history: You have no control over the amount of estrogen that your ovaries produce over time. If you were very young when you got your first period, or you had a late menopause, or both, you have had more years of exposure to estrogen and other hormones produced by your ovaries. Women who had their first period before they were 12 years old or went through menopause after 55 have a higher risk of breast cancer than women with fewer years of exposure to hormones made by the ovaries.

Race: Breast cancer in the United States occurs more often in white women than Latina, Asian, or African American women. But in women 40 and younger, African American women have the highest risk.