Genetic Variant May Significantly Lower Risk of Breast Cancer in Women With History of Preeclampsia

Key Points

  • 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 (IGF1R) compared to women carrying no T alleles.
  • This decrease in risk increased to 90% if the pregnancy with preeclampsia occurred before age 30.

Researchers have demonstrated that women with a history of preeclampsia 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. Their findings were published by Powell et al in Cancer Causes & Control.

The research, directed by lead author Mark Powell, MD, MPH, Director of the Breast Cancer Prevention Project at Zero Breast Cancer, San Rafael, California, and Christopher Benz, MD, Professor of Cancer and Developmental Therapeutics at Buck Institute for Research on Aging, Novato, California, was carried out in the large California Teachers Study.

Study Findings

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 (IGF1R) compared to women carrying no T alleles. This decrease in risk increased to 90% if the pregnancy with preeclampsia occurred before age 30.

“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 Dr. Powell, who is a visiting scientist at the Buck Institute.

Dr. 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. Drs. 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. Working with the Komen Tissue Bank, they 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,” Dr. 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 United States whose risk could now be more accurately assessed, resulting in enhanced individualized breast cancer screening protocols.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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