Dr. Deborah M. Winn, Associate Director (Acting), Epidemiology and Genetics Research Program
These are exciting times for those of us in the field of cancer epidemiology and a thrilling time to be at the National Cancer Institute. Major shifts are occurring in how epidemiologists work together and with the greater scientific community, the types of scientific questions they are asking, the technical approaches they are using to answer fundamental questions of cancer etiology, and the uses to which epidemiology is being put. These remarkable changes are likely to yield new insights into causes of cancer and potential applications to prevent and ameliorate the consequences of cancer.
The staff of the Epidemiology and Genetics Research Program (EGRP) are working directly with grant applicants and grantees to advance cancer epidemiology by advising them on funding mechanisms and on NCI’s and EGRP’s scientific priorities, as well as by monitoring scientific progress. Another important role of program staff in moving research forward is through development of funding initiatives and by developing scientific partnerships across NCI and NIH.
Epidemiologists have long recognized that cancer development is a multistep process. Both genetic and environmental factors influence cancer development, and there may be multiple genes involved, each with a potentially small effect. Studies with large numbers of participants are needed to unravel the distinct contributions of these multiple potential risk factors.
Epidemiologists are increasingly aware of the importance of achieving sample sizes that are often beyond the size of any given study and now are frequently creating scientific consortia to address scientific questions in cancer epidemiology. Consortia are groups of investigators who jointly pool data from their studies to enable analyses of data and biospecimens using larger numbers of study participants than would be possible by any single investigator’s study. There are consortia that include investigators engaged in case-control studies of a particular tumor type, who are responsible for large population cohorts, and investigators who study families at high risk to understand genetic factors in cancer etiology. EGRP is taking a major role in developing and encouraging the formation of consortia in many different ways, including serving on steering committees that govern these collaborative teams, as well as providing advice on best practices, guidance on obtaining funding, and meeting support.
EGRP is also providing funding support to expand the type of scientific questions being asked in epidemiologic studies based on new discoveries in basic sciences. For example, EGRP has organized scientific conferences on both epigenetics and on mitochondrial DNA and the role that these biologic processes may play in cancer etiology. Epigenetic research focuses on reversible heritable changes in gene or cell function that occur without a change in DNA sequence. Mitochondrial DNA is the genetic material of the mitochondria, the organelles that generate energy for the cell. EGRP has brought together epidemiologic experts and basic scientists to develop a research agenda to move the technologies into population settings to answer questions about the epidemiology of cancer. EGRP works extensively with epidemiologists and scientists in other disciplines in NCI’s Division of Cancer Epidemiology and Genetics and elsewhere across NCI and NIH, and makes contributions to the institutes through service on key committees and working groups, such as a major NCI committee on biospecimen repositories. Building and sustaining these relationships promotes transdisciplinary approaches to synergize scientific discovery.
There has been a fundamental change in approaches to understanding the role of genetics in cancer etiology now that the costs are within reach to apply the technology for conducting genomewide scans to large populations. Genome-wide association studies are defined as any study of genetic variation across the entire genome that is designed to identify genetic associations with cancer; these studies examine differences between people with cancer and control groups of people without cancer at hundreds of thousands of points across the genome. There are enormous challenges in the design, validation, and analysis of these studies and EGRP is helping to foster interchange among grantees to address these challenges, as well as contributing to NCI and NIH policies on these issues.
Epidemiologic studies help identify causes of cancer and increase our understanding of the biologic basis of cancer development, but also result in findings that provide tangible benefits to public health and clinical practice, as well as address questions of real concern to thepublic. EGRP supports investigators who undertake studies to understand the basis of racial and ethnic disparities in cancer incidence, risks associated with positive family history of cancer, the role of energy balance in cancer development, risks from taking certain medications, and how viruses cause cancer, among others. Additionally, EGRP is partnering with the National Institute of Environmental Health Sciences to better understand environmental factors influencing puberty in girls as a way of understanding how this potential window of susceptibility for breast cancer may be involved in breast cancer etiology. The role of environmental factors in breast cancer development has long been an issue of public concern. Findings from grantees’ studies also may lead to the development of interventions and approaches to prevent cancer, detect it earlier, and reduce morbidity and mortality among people with cancer. Epidemiologic findings often also provide the scientific basis for changes in public health and clinical practice.