Citizens of Hope - Researchers - Leslie Bernstein

Imagine if women could actually do something to reduce their breast cancer risk. Leslie Bernstein, Ph.D., not only imagined it -- she proved it worked.
A biostatistician and epidemiologist, Bernstein cares deeply about how to prevent disease. That commitment led her to be one of the first scientists to study exercise as a tool to reduce breast cancer risk.

Researchers know that female hormones like estrogen are linked to breast cancer’s development and growth. The longer women are exposed to higher levels of these hormones over their lifetime, the greater their risk.

Scientists once thought that exposure couldn’t be changed much, but Bernstein challenged that idea.

“We sat back and asked, ‘What can lower your estrogen levels?’ — and we started looking at exercise,” said Bernstein, chief of the Division of Etiology in the Department of Population Sciences and dean for faculty affairs.

Over her career, she has studied girls and women of nearly all ages to understand how their physical activity influenced hormone levels and ultimately their breast cancer risk.

Her findings have shown that even moderate, regular activity like walking can lower exposure to female hormones and reduce risk. The results bear out in ongoing studies she leads, too, such as the California Teachers Study , an investigation of health and risk factors among female educators in the California public school system.

Bernstein wants to inspire others to strike out on their own scientific quests against cancer. Throughout her career, she’s mentored more than 100 young scientists who are successfully driving cancer research nationwide.

“Many questions still remained to be answered about factors influencing breast cancer risk,” said Bernstein, professor emeritus and AFLAC Chair Emeritus in Cancer Research at the University of Southern California, in addition to her role at City of Hope. “The good news is that many promising scientists are looking for these answers.”