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How We Study

DCEG investigators utilize a variety of research approaches in seeking to understand the causes of cancer. 

Absolute Risk Modeling

DCEG investigators in the Biostatistics Branch have developed models (such as the Gail model) for projecting the individualized absolute risk of certain types of cancer. These models have been used to counsel individual patients on their disease risk; to make more formal management recommendations, such as whether or not to take tamoxifen to prevent breast cancer; to design cancer prevention trials; and to assess the potential reductions in population absolute risk from preventive activities. Learn about DCEG absolute risk models for breast cancer, colon cancer, and melanoma.

Descriptive Epidemiology

The Division maintains a broad-ranging, multi-faceted program of descriptive epidemiological studies utilizing a variety of methodological approaches to identify novel risk factors, evaluate tumor heterogeneity, describe current and future trends of common and rare malignancies, and project risk for second primary cancers. See examples of descriptive epidemiology studies.

Exposure Assessment Studies and Methods

Evaluating exposure-response relationships is a crucial component in determining cancer causation. For that reason, quantitative exposure assessment plays an essential role in high-quality epidemiologic investigations. DCEG investigators have developed cutting-edge tools and techniques to evaluate the reliability and validity of exposure measurements used in cohort and case-control studies of occupational, lifestyle, and environmental exposures. In addition, our investigators continually work to improve upon these well-established methods. See examples of exposure assessment studies and methods

Genomic Studies

DCEG investigates the biological basis of inherited and acquired genetic variants associated with cancer susceptibility, utilizing genome-wide association studies, exome sequencing, and candidate gene studies. DCEG investigators and their collaborators employ an array of advanced statistical methods to support these studies. Learn more about genomic studies.


Metabolomics is the study of small-molecule metabolites in cells, tissues, and organisms that are present in biofluids such as plasma and urine. An emerging field of study, metabolomics has the potential to improve exposure measures and delineate mechanistic links between exposures and cancer. Learn about early-stage DCEG research in metabolomics.

The Human Microbiome and Cancer

The human microbiota is the collection of all the microorganisms and bacteria that live in or on the human body, such as those present in the digestive system. In the emerging field of microbiomics, researchers study the extent and patterns of these microbes at various body sites and their influence on human health and disease. DCEG investigators are at the forefront of both methodologic and cancer association studies of the microbiome in human populations. Learn about early-stage DCEG research in microbiomics.

Molecular Epidemiology

We use molecular epidemiology to examine the relationship of genetic and environmental risk factors to cancer etiology. Using laboratory techniques, investigators look for biomarkers of disease and use them to understand the underlying mechanisms of disease in populations. Read about Biomarker Tools developed by the Biostatistics Branch and Clinical Epidemiology Unit.

Interdisciplinary Working Groups

DCEG scientists form collaborative working groups to enhance the exchange of information and support interdisciplinary approaches to epidemiological and genetic research. Working groups draw their members from across the Division and other organizations in NCI, enabling them to apply a wide range of expertise to the study of complex questions. Read more about Interdisciplinary Working Groups.

Psychosocial Effects of Cancer Predisposition Syndromes

The Clinical Genetics Branch investigates and defines best practices of medical, psychosocial, and genetic counseling, as well as risk assessment and communication, to counsel and care for at-risk individuals and families. Read more about research on the Psychosocial Effects of Cancer Predisposition Syndromes.

Tumor Profiling in Relation to Cancer Etiology

The recognition of cancer as a heterogeneous disease, coupled with technological advances in molecular/genomic profiling of tumors, provides epidemiologists with the opportunity to integrate tissue profiling in etiologic studies to study the carcinogenesis process, and pinpoint specific factors associated with risk for developing specific molecular or genomic cancer subtypes. DCEG investigators are also undertaking foundational research to identify novel molecular and genomic signatures in tumors linked to germline genetic variants and certain environmental exposures. Learn about tumor profiling research.