• Voices of Impact – Dr. Anna Wu / Dr. Iona Cheng



     Dr. Anna Wu (USC) and Dr. Iona Cheng (Cancer Prevention Institute of California) have designed what will be one of the largest and most in-depth studies addressing whether outdoor air pollution is associated with increased breast cancer risk. Their study was selected for funding under the Komen Challenge Grants focused on the environmental causes of breast cancer.

    Anna Wu, Ph.D., Los Angeles, CA – Researcher 
    Iona Cheng, Ph.D., Oakland, CA – Researcher

    Dr. Wu (left): “Since I first worked on the role of passive smoking and lung cancer in women some 20 years ago, I have been interested in air pollution – indoor and outdoor – in relation to cancer risk. This is a topic that has been discussed in relation to breast cancer for a while, but it’s been difficult to study.”

    Dr. Cheng (right): “My work focuses on understanding the role of genetic, lifestyle, and neighborhood factors such as air pollution, in relation to cancer risk – and, in particular, the contributing factors that drive racial and ethnic differences.” 

    We’ve known each other for about 10 years; we first met at USC and more recently because of a collaborative Breast Cancer Survivorship Study in California, and realized we have numerous mutual interests in similar research topics. Both of us have backgrounds in epidemiology, investigating how geographical, racial and ethnic differences could affect similar groups of individuals in completely different ways.

    Breast cancer is a very serious disease that continues to kill hundreds of thousands each year, yet we have a limited understanding of what actually causes it. We recognized a need to leverage our professional interests and backgrounds to study the impact that air pollution might have on breast cancer risk.

    With more than $100 million invested in research focused on prevention and causation of breast cancer, Komen is deeply invested in this subject. Although questions about air pollution are of immense public health interest and importance, they have not been adequately addressed and remain under-explored, in part because of important methodological difficulties.

    As co-principal investigators of this project, we have designed a study to address many of the challenges noted in the past. Californians are exposed to one of the highest levels of air pollution in the nation; vehicle exhaust is a major contributor to air pollution in California, leading the nation in the number of registered vehicles and in total motor fuel use. We plan to link air pollution data to individual health factors such as education, number of children, and body size to collectively examine their impact on breast cancer risk. A major difference of this study with prior research is that it will also take into account place of residence, timing of exposure, genetic makeup, and socioeconomics.

    In addition, we will conduct the study in a unique population: the Multiethnic Cohort (MEC), with more than 60,000 women, including 19,000 African Americans and 24,000 Latinas in California. By studying these populations, we hope to be able to identify the role of traffic-related air pollution and whether there are subgroups that may be particularly vulnerable to its effects on health.

    The MEC maintains accurate and up-to-date addresses on all participants, achieved through periodic mailings of newsletters and questionnaires, as well as linkages with resources as credit agencies, since its inception 19 years ago. A complete address history is maintained for every participant. We have excellent residential history data with baseline and follow-up addresses for 60,756 female MEC participants residing in Los Angeles County. We thought this would be a great opportunity to use the Multiethnic Cohort study, and are excited to be able to pursue this topic.

    Studying the effects of air pollution is difficult, since it is a complex mixture of a large number of chemical compounds derived from vehicle traffic, heating systems, industrial plants, and others. This is why we will utilize three different – but complementary – measures of traffic pollutants that have been used successfully in studies of birth outcomes and childhood cancer.

    If the results show that there is a relationship between being exposed to traffic-related air pollution and breast cancer, the potential impact of these findings has widespread significance, as more than 127.2 million Americans live in 235 counties with unhealthy levels of air pollution. This will undoubtedly have important implications not only in California and elsewhere in the US, but also worldwide, particularly in urban areas with much higher pollution levels, such as in China, India, Mexico.

    We are thrilled that Komen is funding the Challenge Grants, as there is an incredible potential to increase current knowledge on the impact of the environment in breast cancer. It’s very exciting to be part of one of the first studies that will allow us to look at this topic in multiple racial/ethnic groups. The results of these studies will provide strong evidence for or against the association between each traffic-related air pollutants and the risk of breast cancer.

    The fact that Komen is specifically interested in the environment in this most recent grant cycle really speaks highly in terms of Komen’s interest in examining topics that have not to date been addressed sufficiently. This commitment by Komen is important and timely, and we’re very grateful for the opportunity.

    Learn about Komen’s 2013 grant portfolio, including:
    Environmental / Metastatic Research / Screening / Disparities in Outcomes / Immunology

    View a complete list of Komen’s 2013 research funding

    Interested in the Komen Challenge grants? Read the Institute of Medicine report, funded by Komen, which set the base for the Challenge grants:

    Breast Cancer and the Environment: A Life Course Approach

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