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Did you know?

  • We envision a world free from cancer.

    Our research scientists and their teams collaborate with colleagues around the world to conduct cutting-edge research using large data-sets to:
    • understand the causes of cancer
    • find ways to prevent it or detect it early
    • improve outcomes for cancer survivors 
  • Our mission began more than 40 years ago.

    Established in 1974 as the Northern California Cancer Program, the organization later became known as the Northern California Cancer Center. The name was changed again in 2010 when it became the Cancer Prevention Institute of California (CPIC), which reflects the organization's broader scope and demonstrates its large scale impact of preventing cancer before it starts.
  • We are an independent research institute and a valued partner to many.

    Through its collaborative approach, CPIC also serves as an asset to the nation’s leading cancer fighting organizations, including the National Cancer Institute, and to scientists worldwide, educators, patients, and clinicians, and is affiliated with the Stanford Cancer Institute.
  • We work hard to understand who gets cancer and why.

    Our scientists are frequent contributors to major scientific journals, and often present their findings at important cancer-related conferences. CPIC research has been covered by numerous local, national and international media outlets, such as The New York Times and The Washington Post.
  • Every case of cancer counts…and is counted.

    CPIC operates the Greater Bay Area Cancer Registry as part of the National Cancer Institute's Surveillance, Epidemiology and End Results program and the California Cancer Registry. As required by law, the registry gathers data from hospitals and doctors on all cancers diagnosed and treated in nine Bay Area counties. This information is used to produce cancer statistics and as a platform for research to understand cancer occurrences and survival. Our registry regularly earns Gold Standard Certification by the North American Association of Central Cancer Registries.
  • Our educational efforts reach people of all ethnicities and backgrounds.

    Our Community Education team provides important information to cancer survivors, health professionals and others through conferences and publications on many cancer-related topics including employment, patient advocacy, care giving, specific cancers, and treatments.

  • Breast cancer rates decline when hormone therapy is stopped.

    CPIC was first to report on the alarmingly high and increasing rates of breast cancer in the Bay Area and Marin County in the 1990s. In subsequent studies, CPIC found that when women stopped taking hormone replacement therapy, breast cancer rates declined immediately and dramatically. This showed that hormone therapy was a major contributor to the high rates previously reported and identified one clear path to breast cancer prevention.
  • Our work to associate tanning beds and melanoma prompted legislation.

    CPIC described increased occurrence of melanoma in young women in California, particularly in high socioeconomic areas, implicating use of tanning beds as one cause. This finding led to passage of the first statewide legislation to ban minors from using tanning beds, which should ultimately reduce occurrences of deadly melanoma in young persons.
  • Physical activity lowers your risk of Breast Cancer

    CPIC found that risk of breast cancer was lower for women engaging in more physical activity, such as walking and biking, doing household chores and yard work, and being active on the job. This shows a simple and practical way women can help prevent breast cancer from occurring.
  • Second-hand smoke increases the risk of lung and breast cancer.

    CPIC studies have shown that women exposed to second-hand tobacco smoke have a higher risk of lung cancer even if they don't smoke, and that exposure to household smoke increases their risk of breast cancer over and above the risk they incur from smoking themselves. These findings have been important in leading to anti-smoking legislation.
  • Vitamin D may reduce the risk of prostate cancer.

    CPIC assessed whether sun exposure, which is the main source of vitamin D, is related to prostate cancer risk. Using the difference in skin color measured on the forehead and upper underarm as an indicator of sun exposure, the study found that prostate cancer risk was reduced by 50% in men with a high sun exposure index, with an even higher reduction in risk noted in men with certain alterations in the vitamin D receptor gene.
  • Survival outcomes differ among Asian women of different ethnic backgrounds.

    CPIC was the first to show that breast cancer survival is not uniform across women of different Asian ethnicities, irrespective of how advanced the cancer was when diagnosed. In California, Korean, South Asian and Vietnamese women had the poorest survival after breast cancer, pointing to the need in these communities for better screening and/or breast cancer treatment.
  • Melanoma is on the rise throughout California.

    CPIC demonstrated that the rates of both early and more advanced melanomas were rising in all populations in California. This disturbing finding signals a true and alarming epidemic of this deadly cancer, and it has been cited over 245 times in the medical literature since 2009 because it identifies a major public health problem.
  • Survival disparities occur across many cancer types.

    CPIC showed that survival after follicular lymphoma, a common form of this cancer, is lower in poorer communities than in more affluent communities. This demonstrates population disparities in cancer treatment and shows a need in poorer communities for more access to skilled lymphoma care, including access to new successful drug treatments.
  • Our nail salon studies have widespread positive impact.

    CPIC found that California nail salons had higher than expected levels of carcinogens and other banned substances in the air, identifying the need for better standards and the importance of clarifying whether such exposures lead to cancer and other undesirable health outcomes.
  • Tailored approaches to healthcare are needed to address cultural differences.

    CPIC used two approaches to learn how best to help Vietnamese communities in California receive lifesaving colorectal cancer screening: one approach involved lay health workers directly educating the community on the importance of screening, and the other involved advertising about colorectal cancer screening. CPIC found that the use of lay health workers worked best to improve the screening rate, proving that organized community involvement improves colorectal screening practices among Vietnamese-Americans in California.
  • Lung cancer afflicts nonsmoking women more than men.

    CPIC was the first to show definitively that among nonsmokers, women were more likely than men to have lung cancer. Until this paper, there were no hard data about the incidence of lung cancer in nonsmokers. This study has been cited extensively as motivation for other research to understand the reasons why.
  • Genetic screening is especially important for African American and Hispanic women.

    CPIC was the first to study the level of BRCA1 mutations (genetic changes responsible for increased risk of breast cancer) in nonwhite women. This work found that young African American and Hispanic women with breast cancer had a particularly high prevalence of BRCA1 mutations, and signaled the importance to these communities and their doctors of screening for this mutation when indicated.

CPIC Studies

California Teachers Study (CTS)

The California Teachers Study (CTS) is a major long-term research study initiated by CPIC in partnership with other California universities and research institutes. The CTS is a statewide health study of over 133,000 female current and former teachers and school administrators originally recruited from teacher retirement records. The top priority of the CTS has been to find the causes of breast cancer. However, investigators also use CTS data to understand women’s health more broadly, including studying risk factors of other cancers, asthma, cardiovascular disease and death, stroke, and overall longevity.

How We Collect the Data
How We Use the Data
Some of Our Findings
Selected Research Projects
CTS Collaborators
CTS Information Sheet

How We Collect the Data

Starting in 1995, researchers at CPIC and other collaborating institutions gathered information from CTS participants using an extensive questionnaire asking about their diet, physical activity, medical history, reproductive history, and other aspects of their lifestyle. Every few years, the participants fill out a new questionnaire with updated or new information about changes in their health and lifestyle. 
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How We Use the Data

The research team follows the health of each CTS member by linking participant data with data in California statewide databases that provide information on individual cancer diagnoses and details, deaths and specific causes of death, and hospitalizations. Tracking participants’ health in this way provides a highly accurate summary, allowing for high-quality research.

Study data are being used to understand how various factors work independently or together to cause cancers. These factors include genetics, obesity, diet (especially cruciferous vegetables and plant-based estrogens), physical activity, alcohol consumption, early life exposures (including those thought to be relevant to immune system development), medications taken in adulthood (like menopausal hormone therapy and aspirin), and exposure to environmental toxins such as tobacco smoke, pesticides, and air pollution.
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Some of Our Findings

CTS data have provided numerous insights into the health of California women. Among other findings, they have revealed that teachers have different risks of cancer than women of similar age and race in California. Teachers were more likely to develop breast, endometrial, ovarian and thyroid cancer, melanoma, lymphoma, and leukemia than comparison women. Teachers, however, were less likely to be diagnosed with cervical or lung cancer. These observations have helped us focus our efforts on trying to understand the causes and prevention of cancer in women. Our targeted research studies have attracted substantial federal funding, and many scientific publications describe CTS results, helping to advance cancer prevention.
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Selected Research Projects utilizing CTS data at CPIC

Diet, Alcohol and Cancer
CPIC investigators have evaluated extensively the relationship between diet and risk of breast cancer. We found that if a woman is using hormone therapy, drinking two or more alcoholic beverages a day increases her risk of breast cancer. One drink per day - which helps reduce the risk of heart disease - did not increase breast cancer risk in teachers. A woman’s current drinking habits were shown to be more important than past drinking. The combination of alcohol consumption (2+ drinks per day) and use of hormone therapy was associated with the greatest breast cancer risk.

Through our ongoing studies, we are also researching how diet, medication use, and alcohol consumption may be related to cancer, stroke, and death. We are looking at how genetic differences may influence alcohol metabolism. Other important CTS investigations in the area of diet include studying the compounds found in particular plant foods (e.g., cruciferous vegetables such as broccoli and cauliflower) and whether they may reduce the risk of developing breast and endometrial cancers.

Cadmium and Breast and Endometrial Cancers
Cadmium is a carcinogenic metal that exhibits estrogen-like activity. The major sources of non-occupational exposure to cadmium include cigarette smoke, diet (leafy vegetables and seafood), and inhalation of contaminated indoor air. CPIC researchers are currently evaluating how dietary and environmental sources of cadmium may contribute to a woman’s total exposure to this metal and her risk of breast and endometrial cancers.

Light-at-Night, Hazardous Air Pollutants, Persistent Organic Pollutants and Breast Cancer Risk
Our research in these areas seeks to understand how these important environmental exposures may contribute to breast cancer development. The exploratory light-at-night study uses satellite imagery data, in combination with CTS questionnaire data and urinary measures of melatonin, to evaluate the hypothesis that internal body clock disruption from exposures to light at night may be related to breast cancer risk. We are gathering and testing blood samples to evaluate the risk of breast cancer associated with body burden levels of persistent organic pollutants (POPs). This study is the first large-scale cancer study conducted on polybrominated diphenyl ethers (PBDEs) and other flame retardants in humans.

Early-life exposures to microbes, farm living, and later cancer
The “hygiene hypothesis” holds that early-life exposure to microbes (bacteria and its byproducts)—by, for example, living on a farm, or with frequent exposure to animal pens or household pets—prevents asthma and allergy, perhaps by priming the immune system. In our most recent CTS questionnaire, we asked CTS participants about some early life exposures to barns, stables, pets, and children, in order to understand if these factors are associated with later risk of cancer. Our interesting preliminary results suggest that living near barns and stables may play a protective role against thyroid cancer. We are currently following up these results, as well as evaluating the role of these factors in relation to cancers of the breast, endometrium, colon, and melanoma.

Second-Hand Smoke and Cancer
The CTS represents one of the largest studies of tobacco exposures and colorectal cancer risk ever conducted. CTS data have been used to assess the relationship between lifetime exposure to second-hand smoke (i.e., "passive smoking") and breast cancer. We found that while current smoking increases the risk of breast cancer, current exposure to household second-hand smoke does not. We are currently evaluating the role of lifetime exposure to second-hand smoke, as well as exposure in the work place and social settings, in relation to breast cancer risk. We are also examining the roles active and passive smoking may play in the development of colorectal cancer.

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CTS Collaborators

The CTS is a collaborative study conducted by researchers all over the state of California, including CPIC, the City of Hope National Medical Center, the University of Southern California, and the University of California, Irvine. Funding has been provided primarily by the National Institutes of Health, but also from the state of California, and the US Department of Defense.

For more information about the California Teachers Study, please visit
CPIC Investigator(s):
Peggy Reynolds, Ph.D., David O. Nelson, Ph.D.
Other Investigator(s):
Leslie Bernstein, Ph.D., Huiyan Ma, Ph.D., Yani Lu, Ph.D., James V. Lacey, Jr., Ph.D., and Sophia Wang, Ph.D. (City of Hope National Medical Center); Dennis Deapen, Dr.P.H., and Eunjung Lee, Ph.D. (University of Southern California); Hoda Anton-Culver, Ph.D. and Al Ziogas, Ph.D. (University of California, Irvine)
National Cancer Institute
Funding Period:
Study Website: