Researchers have demonstrated that women with a history of preeclampsia, a pregnancy complication characterized by high blood pressure, have as much as a 90% decrease in breast cancer risk if they carry a specific common gene variant. Further studies are now underway to determine the mechanism of this protection in an effort to develop new breast cancer prevention strategies for all women. The study is now online in Cancer Causes & Control, and can be found here.
The research, directed by lead author Mark Powell, MD, MPH, and Buck Institute professor Christopher Benz, MD, was carried out in the large California Teachers Study. Women with preeclampsia were found to have a 74% lower risk of the most common type of breast cancer (hormone receptor positive) if they carried two T alleles of a variant of the insulin-like growth factor receptor gene when compared to women carrying no T alleles. This decrease in risk increased to 90% if the pregnancy with preeclampsia occurred before the age of 30.
"We are thrilled to work with researchers from our Scientific Advisory Board on this exciting project with the potential for developing a new approach to prevention. This very much fits with our goal of reducing the risk of breast cancer," said Rose Barlow, Executive Director of Zero Breast Cancer, which administered the study with funding from the Avon Foundation for Women.
"This research could contribute to understanding the key impact of pregnancy on breast cancer risk, and may help explain why some women are protected while others are not," said Powell, who is a visiting scientist at the Buck Institute and is Director of the Breast Cancer Prevention Project.
Powell said women who develop high blood pressure in pregnancy have many associated changes in levels of hormones and growth factors, resulting in permanent protective breast tissue changes in women who carry the specific common gene variant. Powell and Benz are now working on a major collaborative effort to identify the mechanism of this protective effect with the goal of developing badly needed new prevention strategies. "Fellow researchers have demonstrated enormous interest in working with us," said Benz, who is also a practicing oncologist at the University of California San Francisco (UCSF). "This collective endeavor includes breast cancer investigators from UCSF, the Mayo Clinic, and many other leading research institutions." Working with the Komen Tissue Bank, Powell and Benz have obtained breast tissue from women identified as having high levels of protection, and are now analyzing this tissue in an effort to apply this naturally occurring process to all women.
"These study results may have a more immediate application in risk assessment," Powell added. "Research has shown this decrease in risk applies to women with gestational hypertension who carry the protective gene variant as well as those with preeclampsia. It is estimated that there are 9 million women in the U.S. whose risk could now be more accurately assessed, resulting in enhanced individualized breast cancer screening protocols."
Powell says the study results confirm and expand upon earlier findings from the Marin Women's Study, which consists of 13,344 Marin women whose contribution to this research cannot be overstated. Results were compelling enough to warrant validation in the larger California Teachers Study (CTS), which is a major long-term research study initiated in 1995 by the Cancer Prevention Institute of California (CPIC), and is comprised of 133,479 active and retired female public school teachers and administrators. This study was completed in collaboration with CPIC Senior Research Scientist Peggy Reynolds, PhD, MPH.
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Citation: Functional IGF1R variant predicts breast cancer risk in women with preeclampsia in California Teachers Study DOI: 10.1007/s100552-017-0942-7
About the Buck Institute for Research on Aging
The Buck Institute is the U.S.'s first independent research organization devoted to Geroscience - focused on the connection between normal aging and chronic disease. Based in Novato, CA, The Buck is dedicated to extending "Healthspan", the healthy years of human life and does so utilizing a unique interdisciplinary approach involving laboratories studying the mechanisms of aging and those focused on specific diseases. Buck scientists strive to discover new ways of detecting, preventing and treating age-related diseases such as cancer, Alzheimer's and Parkinson's, cardiovascular disease, macular degeneration, osteoporosis, diabetes and stroke. In their collaborative research, they are supported by the most recent developments in genomics, proteomics, bioinformatics and stem cell technologies. For more information: http://www.thebuck.org
About Zero Breast Cancer
Zero Breast Cancer promotes breast cancer risk reduction through translation of scientific research and evidence-based recommendations that support health and wellness at key stages of life. Our vision is a world with zero breast cancer. The work of ZBC takes place in the context of understanding that cancer risks are not clear cut or sudden; they are complex, they interact and they are embedded in our physical and our social environments. Therefore, risk reduction and prevention efforts must be integrated, multi-faceted, incremental and sustained. ZBC focuses on modifiable risk factors - things that we can change - either individually or within our community. http://www.zerobreastcancer.org
About the Cancer Prevention Institute of California
The Cancer Prevention Institute of California manages the California Teachers Study and is a nonprofit organization dedicated to preventing cancer and to reducing its burden where it cannot yet be prevented. We are the only freestanding research institution working solely to prevent cancer using extensive population data. Our researchers study a wide range of cancer risk factors, such as racial/ethnic background, socioeconomic status, age, occupation, gender, genetic predisposition, geographic location, environment and lifestyle to determine how these factors affect frequency, distribution and types of cancers. For more information, visit the CPIC website at http://www.cpic.org
Journal
Cancer Causes & Control