Breast Cancer

• Breast cancer ranks as the most common form of cancer and second-leading cause of cancer death among women in the United States.
  
  
• Breast cancer can occur in any breast tissue, including the cells that produce milk (called lobular carcinoma) and the ducts that carry milk to the nipple (called ductal carcinoma). Although ductal breast cancer is the most common form, researchers have observed that cases of the less-common lobular cancer have been steadily rising.

Breast cancer risk factor research:

Combined hormone-replacement therapy – In the largest study of its kind, research by Dr. Christopher Li found that postmenopausal women who take combined estrogen/progestin hormone-replacement therapy for at least three years are four times more likely to develop various forms of lobular breast cancer. Learn more »

Exercise and weight – Dr. Anne McTiernan and colleagues have found that postmenopausal women who keep their weight in check and exercise regularly have a significantly lower risk of developing breast cancer. The multicenter study was part of a long-term national study called the Women's Health Initiative. Learn more »

Alcohol consumption – A study led by Dr. Polly Newcomb found that women who consumed 14 or more drinks per week, regardless of the type (wine, liquor or beer), faced a 24 percent increase in breast cancer compared with non-drinkers. Learn more »

Genetic susceptibility – A multicenter research study painted one of the clearest pictures yet of mutations in genes that indicate susceptibility to breast cancer—findings that could help identify women who would benefit from genetic testing. The comprehensive study tracked the prevalence of mutations in BRCA1 and BRCA2 genes in African-American and Caucasian women and examined factors, such as age at breast cancer diagnosis, that predict the likelihood of such mutations. Learn more »

Smoking – Older women who have smoked for 11 or more "pack years"—the lifetime equivalent of a pack a day for at least 11 years—face a 30 to 40 percent increased risk of developing breast cancer as compared to women who've never smoked, according to a study by Dr. Christopher Li and colleagues. What's more, the study found that long-term smokers who also take combination hormone-replacement therapy increase their odds of getting breast cancer by 110 percent. Learn more »

Breast density – A study co-authored by Dr. Emily White found that women whose breasts contain less fatty tissue were more likely to develop breast cancer than those with dense breasts that contain more fatty tissue. The findings, which were based on data collected from more than 1 million women, suggest that a woman's breast density is nearly as important as her age in determining her risk of developing the disease. Learn more »

Fetal cells: Drs. V.K. Gadi and J. Lee Nelson led a study that found cells from a fetus that persist in a woman's body long after pregnancy—a common occurrence known in as fetal microchimerism–is associated with a reduction in a woman's risk of breast cancer. Learn more »

Birth control pills: Taking oral contraceptives for a year or more may increase a woman's risk of developing triple-negative breast cancer, a rare breast form of the disease. The study, led by Dr. Kathi Malone, found that women 40 and under faced a 4.2-times greater risk of developing the disease. Using contraceptives for a longer period of time and starting use at an early age further increased this risk. Learn more »

Refining breast cancer detection –Dr. Nicole Urban and colleagues are evaluating potential biomarkers that may help identify aggressive forms of breast cancer that mammograms don't detect. Researchers are also looking at whether evaluating multiple biomarkers together can help detect different types of malignant and pre-malignant breast cancer. The work is part of the multi-institutional Breast Cancer Center of Excellence project, funded by the Department of Defense Breast Cancer Research Program that was created in 2002. Learn more »

Leading international research – The Hutchinson Center and Susan G. Komen for the Cure lead the Breast Health Global Initiative, an alliance founded in 2002 that includes several internationally focused health care organizations. The BHGI has released numerous sets of guidelines including the recommendation that low- and middle-income countries should implement breast cancer detection programs. Dr. Benjamin Anderson, the BHGI's director, said the recommendation is intended to help policymakers in nations where fatality rates are higher because early detection rates are low. Learn more »

Survival protein – Researchers have identified two proteins in the blood that could help doctors to better predict breast cancer patients' long-term odds of survival. Elevated levels of those substances—C-reactive protein (CRP) and serum amyloid A (SAA)—were associated with reduced overall breast-cancer survival, regardless of a patient's age, tumor stage, race and body mass index, according to a study by Dr. Cornelia Ulrich and colleagues. These markers are associated with chronic inflammation, which is known to contribute to cancer development and progression. Learn more »

A study led by Dr. Peggy Porter and colleagues confirmed for the first time that low levels of a certain protein in breast cancer tumor cells are associated with poorer chances of surviving the disease. More than a decade before these findings, the same researchers had identified that the same protein, called p27, prevents cells from dividing. Learn more »

C-peptide – Women with invasive breast cancer and high blood levels of C-peptide, a marker of insulin secretion often associated with obesity and overweight, are three times more likely to die from the disease than women with lower levels of C-peptide, according to a study co-led by Dr. Anne McTiernan. The findings come from the Health, Eating, Activity and Lifestyle (HEAL) Study, a long-term, multicenter observation of breast-cancer patients. Learn more »

Breast cancer and child bearing – Breast cancer patients younger than 45 who later have children are no more likely to die of the disease than patients who do not bear children, according to a study led by Dr. Beth Mueller. The findings are consistent with previous analyses in Scandinavia. Learn more »