Etiology & Prevention

Although our foundation of knowledge for the basic science aspects of breast cancer (tumor biology) has expanded greatly over the past decade, there still remains a gap in our strategies for large-scale prevention due to uncertainties over the underlying causes of the disease and their relative importance. There is an extensive list of factors associated with increased or decreased risk for breast cancer. However, some of these factors (such as diet) remain controversial; how others affect breast cancer (such as socioeconomic status) remains a mystery, and true causes are yet to be discovered.

The two research topics represented in this section are:

Research Concluded in 2009

Breast Cancer Lymphedema: Role of Insulin Resistance/FOXC2
Breast cancer treatments can put survivors at risk of developing lymphedema, which is characterized by chronic swelling of the arm, pain, and loss of mobility. It is difficult to identify which women are at highest risk for lymphedema, and current treatment options are limited and not highly successful. To identify genetic variations that may increase lymphedema risk, Stanley Rockson, M.D., at Stanford University, in Palo Alto, and colleagues analyzed blood samples from women who developed lymphedema after their breast cancer treatment and women who did not. They were specifically interested in a gene, called FOXC, which is associated with insulin resistance and may play a role in lymphatic development. Their studies showed that insulin sensitivity was inversely correlated with lymphedema risk, which suggested that elevated levels of circulating insulin might help repair the lymph system and reduce lymphedema risk. Dr. Rockson intends to continue to investigate the relationship between insulin and lymphedema. Findings from these studies could lead to new ways of determining which women are at increased risk of developing lymphedema, or even prevent it from occurring.

Tea, Genes and Their Interactions on Breast Cancer
Studies have suggested that soy and green tea may reduce breast cancer risk. Anna Wu, Ph.D., at the University of Southern California, in Los Angeles, and colleagues conducted a population-based, case-control study of breast cancer in Asian American women in Los Angeles County to investigate the relationship between consumption of these foods and breast cancer incidence. Dr. Wu and her colleagues found a 50 percent reduction in breast cancer risk among daily green tea users. They also found that breast cancer risk was significantly inversely associated with soy food intake during adolescence and adult life, with significant risk reductions seen in women who ate a lot of soy only as adults. These findings advance our understanding of the role that soy and green tea may play in breast cancer risk reduction. Findings from this research were published in International Journal of Cancer 120(2006)844; Nutrition and Cancer 56(2006)128; Carcinogenesis 28(2007)1561; Journal of Clinical Oncology 25(2007)3024; Human Molecular Genetics 17(2008)825; Nature Genetics 40(2008)259; and American Journal of Clinical Nutrition 89(2009)1145.

Research Initiated in 2009

Breast Cancer Risk Reduction: A Patient-Doctor Intervention
Celia Kaplan
University of California, San Francisco

Cancer Mapping: Making Spatial Models Work for Communities
Eric Roberts
Public Health Institute

Environmental Causes of Breast Cancer Across Generations
Barbara Cohn
Public Health Institute

Exploring Disparities, Environmental Risk Factors in Teachers
Susan Hurley and Peggy Reynolds
Northern California Cancer Center

Mammary Gland Evaluation and Risk Assessment
Lawrence Kushi
Kaiser Foundation Research Institute

Model-building with Complex, High-dimensional Exposures
David Nelson
Northern California Cancer Center

New Paradigm of Breast Cancer Causation and Prevention
Robert Hiatt
University of California, San Francisco

Soy Treatment for High-risk Women and DCIS Patients
Anna Wu
University of Southern California

Research in Progress

Antidepressant and Breast Cancer Drug Interactions
Reina Haque
Kaiser Foundation Research Institute

Breast Cancer Risks in California Nail Salon Workers
Peggy Reynolds and Linda Okahara
Northern California Cancer Center and Asian Health Services

Circuit Training to Lower Breast Cancer Risk in Latina Teens
Jaimie Davis
University of Southern California

FGFR2 Signaling in Human Breast Cancer Cells
Daniel Donoghue
University of California, San Diego

Folate, DNA Methylation and Breast Cancer Metastasis
Teresa Marple
University of California, Davis

Genes in Hormone Metabolism Pathway and Breast Cancer
Eunjung Lee
University of Southern California

Grapefruit, Hormones, and Postmenopausal Breast Cancer Risk
Kristine Monroe
University of Southern California

Pesticide and Gene Interactions in Latina Farm Workers
Paul Mills
University of California, San Francisco

Prognostic Implications of DNA Glycation in Breast Cancer
Daniel Tamae
Beckman Research Institute of the City of Hope

Structural Characterization of Aromatase
Yanyan Hong
Beckman Research Institute of the City of Hope