Cancer Etiology
Examining the causes of cancer

The goal of the Division of Cancer Etiology is to understand the causes of cancer. This knowledge can enable scientists to develop solutions to help reduce cancer risk, especially in people who have the greatest likelihood of developing the disease.

Our researchers
Leslie Bernstein, Ph.D., director of the Division of Cancer Etiology

Among the most accomplished researchers working in cancer epidemiology today, Bernstein was instrumental in identifying physical activity as a means to reduce the risk of breast cancer. She is involved in projects to explore the links between hormone exposures, physical activity, obesity and cancer. She is also examining how breast cancer impacts the lives of women after they are finished with treatment.

Jessica Clague DeHart, Ph.D., M.P.H., assistant research professor
Clague DeHart is examining the genetic and molecular epidemiology of women’s cancers. Her focus is the biological mechanisms underlying associations between modifiable risk factors and cancer risk reduction and survival.


Katherine Henderson, Ph.D., assistant research professor

James V. Lacey Jr., Ph.D., associate professor
Lacey’s work has been key in demonstrating that women using menopausal progestins and estrogens are more likely to develop uterine and ovarian cancer. He is continuing to investigate how hormones affect the risk of developing uterine cancer, ovarian cancer, breast cancer and other diseases among women. He is leading the expansion of the California Teachers Study.
Yani Lu, M.D., Ph.D., assistant research professor
Lu’s research involves breast cancer, blood cancer and other types of cancer, with a focus on etiology and survival.
Huiyan Ma, Ph.D., assistant research professor
The lead manager of the databases that constitute the California Teachers Study, she studies the epidemiology of women’s cancers.  Her primary focuses include understanding the roles of alternative and complementary medicine among breast cancer survivors and identifying the risk factors for different subtypes of breast cancer.


Susan L. Neuhausen, Ph.D., Morris and Horowitz Families Professor in Cancer Etiology and Outcomes Research
Neuhausen’s research is on identifying environmental and genetic stressors that predispose people to disease, focusing primarily on ovarian and breast cancers and celiac disease. She is working to understand why some individuals are more prone to develop certain illnesses, thus allowing the design and implementation of programs to keep those people healthy.


Sophia S. Wang, Ph.D., associate professor
Wang has focused on epidemiological research in cervical cancer and non-Hodgkin lymphoma and understanding the molecular and genetic contributions to cancer causation. She seeks to understand the role of immunity and inflammation in cancers among women. She is also expanding the scope of her research to other chronic diseases for which disease burdens disproportionately affect women.
Research Highlights
California Teachers Study
In 1995 and 1996, 133,479 female teachers and public school professionals in California responded to a request to participate in a large prospective cohort study. Since then, those women have offered information about their lifestyles, health and backgrounds through mailed questionnaires, and some have given biological samples. This huge cache of data has allowed researchers to determine what differentiates the women who have developed cancer from those who have not.
Some of the most recent findings from the California Teacher Study include:
  • obesity is related to an increased risk of pancreatic cancer
  • small particulate air pollution is related to the risk of cardiovascular disease deaths
  • smoking and secondhand smoke may increase the risk of non-Hodgkin lymphoma
  • delayed onset of puberty may be related to an increased risk of thyroid cancer in younger women
  • a decrease in invasive breast cancer is explained in large part by the decline in use of hormone therapy to treat menopausal symptoms. 
Now, in an expansion of the California Teacher Study, researchers are collecting blood and saliva samples from more than 20,000 cohort members with no history of any cancer. This large group of biospecimens, along with data on diet, lifestyle and other factors, will help researchers identify new biomarkers for early detection, predict responses to treatments, and identify genetic and environmental interactions. This new information could lead to better treatments and perhaps prevention of cancer.