Most cancer research in human populations has focused on a range of exposures in the middle to last 25th percentile of the lifespan. While this narrow age range yields the highest number of cancer cases, it is a phase of life in which cancer prevention efforts are more difficult and perhaps less effective.
The emerging evidence that early-life exposures affect cancer development later in life calls for a refocusing of efforts targeting the early-life spectrum: maternal (as well as paternal), in utero, infancy, childhood, and adolescence exposures. This paradigm shift in cancer research has the potential to translate into substantial gains in cancer prevention and control later in life.
Epidemiological studies of early-life factors and cancer development later in life have had significant methodological challenges such as the long latency period, the distinctiveness of each cancer, and the large number of subjects that must be studied, all likely to impact study feasibility and increase study costs. In order to launch both association and mechanistic studies of early-life exposures and cancer development later in life, these hurdles might be mitigated by leveraging several existing large-scale prospective studies in the United States and globally, as well as birth databases and birth cohorts.
Collaborations among NCI and Partners
In May 2011, NCI convened an Expert Panel Workshop on Early-Life Events and Cancer. The proceedings of the 2011 Workshop, including the state of the science, methodological challenges, research gaps, and opportunities were published in the June 2012 issue of Cancer Causes & Control. And in August 2011, the Centers for Disease Control and Prevention (CDC) convened a workshop for identifying opportunities for cancer prevention during preadolescence and adolescence and the proceedings of that workshop were published in May 2013 as a supplement to the Journal of Adolescent Health. In addition, a Trans-Agency Early Life Exposures and Cancer Working Group has been established comprising representatives from multiple Institutes and Centers of the National Institutes of Health and other agencies in the U.S. Department of Health Human Services and the Department of Defense to advance scientific research on early-life exposures and cancer development.
Another relevant effort is the Breast Cancer and the Environment Research Program, which is a set of cooperative agreements co-funded by the National Institute of Environmental Health Sciences and NCI designed to examine the environmental determinants of pubertal timing in girls and the effect of environmental exposures, during critical periods over a woman’s lifespan, on breast cancer risk.
Scientific Funding Opportunities
Currently, there are no cancer research funding opportunities focused exclusively on early-life exposures and events; however, two existing funding opportunities are applicable. These are:
- PAR-13-109, “Mechanistic Insights from Birth Cohorts (R01)”: Studies proposed in response to this announcement must take advantage of existing (or accruing) birth cohorts, with well-characterized pregnancies, to address targeted mechanistic questions regarding the developmental origins of disease, including cancer.
- RFA-TW-13-002, “Research on the Role of Epigenetics in Social, Behavioral, Environmental and Biological Relationships, throughout the Life-Span and across Generations (R21)”: Research plans that are responsive to this RFA will use existing bio-psycho-social and environmental data from human cohorts or animal studies that have biospecimens available for epigenetic profiling. The one year exploratory/developmental awards are expected to generate preliminary data for comprehensive basic research applications to study interactions between epigenetics and social/behavioral/biological/environmental factors in both normal function and pathophysiology throughout life and across generations.
What Do You Think?
Although significant research opportunities do exist in the area of early life exposures and cancer, methodological challenges and limited availability of research resources hinder studies of early life factors and cancer development later in life. EGRP invites you to tell us what issues you think should be considered under this new paradigm to move the field forward. Additionally, EGRP would like to hear of any research resources you have found to be helpful in facilitating research on early life factors and cancer development.
Somdat Mahabir, Ph.D., M.P.H., is a Program Director in the Modifiable Risk Factors Branch of the Epidemiology and Genomics Research Program in NCI’s Division of Cancer Control and Population Sciences. His responsibilities include the scientific management of a research portfolio and initiatives that focus on modifiable cancer risk factors, such as diet and nutrition, obesity/adiposity, and energy balance, including physical activity energy expenditure, alcohol, and early-life exposures/events. Dr. Mahabir serves as the Chair of the Trans-Agency Early-Life Exposures and Cancer Working Group. He is also the scientific contact for PAR-13-109 and is EGRP’s scientific point of contact for the International Childhood Cancer Cohort Consortium (I4C) and the Childhood Leukemia International Consortium (CLIC).
Prior to joining EGRP in 2009, Dr. Mahabir was an Assistant Professor in the Department of Epidemiology, Division of Cancer Prevention and Population Sciences, at The University of Texas M.D. Anderson Cancer Center.