Breast Cancer

Background of Breast Cancer

Cancer can occur in any of the tissues that make up the breast. Cancer that arises in the cells that produce milk is called lobular carcinoma. When it occurs in the ducts that carry the milk to the nipple it is called ductal carcinoma. Ductal carcinoma is the most common type of breast cancer.

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Breast cancer is the most common type of cancer and the second leading cause of cancer death among women in the United States. The disease can also occur in men. According to the American Cancer Society, an estimated 178,480 new cases of invasive breast cancer will be diagnosed among women and 1,690 among men in the United States this year. The exact causes of breast cancer are not known; however, studies show that the risk of breast cancer increases as a woman gets older. The disease is very uncommon in women under age 35 and is most common in women over age 50. The risk is especially high for women over age 60. Breast cancer occurs more often in white women than African-American or Asian women overall; however breast cancer is more common in African-American women than white women under age 45.

Research has shown that a number of other factors also increase a woman's chances of getting breast cancer. These factors include having a family history of cancer defects in one of two inherited genes, called BRCA-1 and BRCA-2 onset of menstruation at an early age and late onset of menopause. Other factors such as never experiencing childbirth and the use of hormones also appear to be linked to increased risk of breast cancer. Recent studies also suggest that the use of alcohol, lack of exercise, and obesity and high-fat diets may play a role in developing breast cancer.

The rate of death related to breast cancer is declining, likely because of efforts to find breast cancer earlier, and improved treatment options.

Hutchinson Center Breast Cancer Research

Overview of Hutchinson Center Breast Cancer Research

The Hutchinson Center is on the forefront of breast cancer research. The broad range of research includes work on the basic cellular mechanisms of cancer development, risk factors, genetics, diagnosis, early detection, prognosis, prevention, counseling and treatment.

In an effort to expedite research progress, the Hutchinson Center formed the Breast Cancer Research Program, a collaborative effort among colleagues at the University of Washington and other institutions. The program, founded in 1995, brings together a multidisciplinary group of scientists and provides a forum for the exchange of ideas and approaches to breast-cancer research through seminars, invited speakers, interdisciplinary research and pilot research project support.

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Combined hormone therapy raises risk

Over the past decade, researchers have been puzzled by the trends in breast cancer. While the occurrence of the most common form, ductal carcinoma, remained constant, a rare but less aggressive form of the disease, lobular breast cancer, has been steadily rising.

A study led by Dr. Janet Daling and Hutchinson Center colleagues found that women under 65 who used combination hormone therapy for at least six months had about a twofold increased risk of developing lobular breast cancer compared to women who do not use such therapy.

Coming on the heels of the Women's Health Initiative's finding of an increased risk of breast cancer among post-menopausal women on hormone therapy, the Daling study sharpens the disturbing picture emerging regarding long-term hormone-replacement therapy as a risk for breast cancer.

For more than 30 years, Daling's research has tracked the origins of reproductive cancers through more than 300 published studies. Her research has clarified the effects of oral contraception, hormone therapies and genetic susceptibility of breast, uterine, ovarian and cervical cancers.

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Exploring the links between diet and cancer

News headlines about the link between diet and cancer have become as familiar as mom's dinnertime admonishment: "Eat your vegetables, they're good for you."

The difference is that Hutchinson Center researchers like Dr. Alan Kristal have begun to quantify how and which vegetables are good for you, as well as how diet is linked to cancers of the prostate, breast, colon and other diseases. Kristal's research focuses on nutritional epidemiology, including the origins of cancer and the relationship between diet and cancer. He also is interested in the implementation and evaluation of public-health nutrition interventions.

In collaboration with his colleagues at the University of Washington, Kristal's current projects include studies of diet, dietary supplements and cancer risk; diet and the progression of Barrett's esophagus, a precancerous condition; and low-fat diet and breast-cancer survival.

In one of these studies, Kristal's team found that eating at least three servings of vegetables a day — particularly the cruciferous variety, such as broccoli and cauliflower — can cut the risk of prostate cancer by 45 percent.

In another study, Kristal and colleagues refined the understanding of the link between dietary fat, excess calcium and prostate cancer. The study showed that fat and calcium themselves may not cause prostate cancer, as previously thought, but instead may fuel its progression from localized to advanced disease. The men in the study whose dietary intake of fats composed no more than 30 percent of their daily calorie intake had half the risk of late-stage cancer compared with men who consumed more fat. However, there were no associations of fat intake with early stage disease.

The hope of research like Kristal's is that the more that is understood about the relationship between diet, nutrition and cancer, the more likely the disease can be prevented.

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Effects of physical activity and exercise on new or recurrent breast cancer

Most people know that exercise can improve cardiovascular health, but many may not know that high-intensity exercise can reduce women's risk of breast cancer by 30 percent compared to women who don't exercise, as determined by Dr. Anne McTiernan and colleagues at Hutchinson Center. McTiernan wants to know how exercise confers this protection against cancer.

In addition to identifying the effects of physical activity and exercise on new or recurrent breast and colorectal cancer, McTiernan is heading several national clinical trials and observational studies testing the effect of exercise on biomarkers of cancer risk. These studies include:

• The APPEAL Study
  The APPEAL Study (A Program Promoting Exercise and Active Lifestyles), is the first to look specifically at how moderate to vigorous exercise may lower risk of colon polyps and colon cancer development.
• The Physical Activity for Total Health study (PATH)
  The Physical Activity for Total Health study (PATH) is a randomized intervention study. This study is examining how exercise affects hormone levels, body fat mass, breast density and quality of life.
• The Immune Exercise Study (IMEX)
  The Immune Exercise Study (IMEX) is a randomized intervention study. Participants in the study include a subset of 117 women from the PATH study. The goal of the study is to examine how moderate exercise affects immune function.
• The ExCel Study
  The ExCel Study is a five-year study looking at whether taking a medication (exemestane) could reduce the risk of developing breast cancer in postmenopausal women at high risk of breast cancer.

Early warning cancer indicators

As with all carefully-designed machines, the molecular components that make cells divide must work smoothly and efficiently, but also must have a braking mechanism to halt cell division. Cancer results from the failure of this system to stop cells from reproducing. If physicians could get an early warning, indicating the "brakes are beginning to fail," they might initiate treatment earlier for breast and other cancers when chances of a cure are much higher.

Thanks to an interdisciplinary team of investigators at Hutchinson Center led by Drs. Peggy Porter, Kathi Malone, Elaine Ostrander, Janet Daling and James Roberts such an indicator may one day become a reality.

One study showed that the production of two proteins known as cyclin E and p27 correlates with cancer progression. As the disease becomes more severe, levels of cyclin E increase while p27 levels decrease. Monitoring these changes in protein levels may help in predicting behavior of tumors or tumor response to specific therapies.

Porter's research team studies the clinical significance of cellular events taking place in the initial stages of premalignant and malignant breast and ano-genital tumors. More recently, Porter's team has begun using deoxyribonucleic acid (DNA) microarray technology to examine genomic alterations that are associated with specific sub-types of breast cancers or with specific groups of women. These studies are designed to identify markers in tissue that predict behavior of early breast neoplasia.

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Quest for a blood test for breast cancer

The Hutchinson Center has been selected to lead a three-year, $9 million project funded by the Entertainment Industry Foundation (EIF) and its Women's Cancer Research Fund (WCRF) to discover proteins in the blood that may signal the presence of breast cancer at its earliest stages. The consortium unites scientists from the Hutchinson Center, Pacific Northwest National Laboratory, Dana-Farber Cancer Institute, University of Southern California/Norris Comprehensive Cancer Center and Hospital, the Institute for Systems Biology, the Broad Institute of MIT and Harvard, and The University of Texas M. D. Anderson Cancer Center.

The effort brings together researchers in the fields of proteomics, informatics and clinical breast-cancer care to share research methodologies, critical data, and tissue and blood samples from human subjects to speed the discovery of biomarkers that may lead to a blood test for early detection of breast cancer.

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Articles Related to Breast Cancer

• Two forms of imaging detect better than one
  
  
• A better detector for breast cancer
  
  
• New model emphasizes denser breast tissue as a predictor of cancer risk
  
  
• Tumor-cell biomarker may predict breast-cancer survival
  
  
• Breast Health Global Initiative receives funds from Susan G. Komen Foundation
  
  
• Low BMI, exercise reduce breast-cancer risk
  
  
• The benefits of exercise before breast-cancer diagnosis
  
  
• Stars in the quest for early detection — Lee Hartwell leads research funded by entertainment industry to pinpoint biomarkers for breast cancer
  
  
• Measure breast-cancer risk in 'pack years' — Li study associates long-term smoking with increased risk of breast cancer; combined HRT may more than double risk
  
  
• ExCellent potential for cancer prevention — PHS leads study of low-risk drug that blocks estrogen production and may prevent breast cancer
  
  
• Working nights may shift biological balance toward breast cancer — Consistent late-night exposure to light can disrupt levels of melatonin, alter hormones related to increased breast-cancer risk
  
  
• Ethnic differences in breast-cancer — Factors like family history, access to screening account for rate differences; mortality rates in African Americans may be an exception
  
  

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