A Review of NCI's Extramural Grant Portfolio: Identifying Opportunities for Future Research in Genes and Environment in Cancer
1DCCPS, EGRP, National Cancer Institute.Cancer Epidemiology Biomarkers & Prevention (Impact Factor: 4.13). 03/2013; 22(4). DOI: 10.1158/1055-9965.EPI-13-0156
BACKGROUND: Genetic and environmental factors jointly influence cancer risk. The National Institutes of Health (NIH) has made the study of gene-environment (GxE) interactions a research priority since the year 2000. METHODS: To assess the current status of GxE research in cancer, we analyzed the extramural grant portfolio of the National Cancer Institute (NCI) from Fiscal Years 2007 to 2009. Publications attributed to selected grants were also evaluated. RESULTS: From the 1,106 research grants identified in our portfolio analysis, a random sample of 450 grants (40%) was selected for data abstraction; of these, 147 (33%) were considered relevant. The most common cancer type was breast (20%, n=29), followed by lymphoproliferative (10%, n=14), colorectal (9%, n=13), melanoma/other skin (9%, n=13), and lung/upper aero-digestive tract (8%, n=12) cancers. The majority of grants were studies of candidate genes (68%, n=100) compared to genome-wide association studies (GWAS) (8%, n=12). Approximately one third studied environmental exposures categorized as energy balance (37%, n=54) or drugs/treatment (29%, n=43). From the 147 relevant grants, 108 publications classified as GxE or pharmacogenomic were identified. These publications were linked to 37 of the 147 grant applications (25%). CONCLUSIONS: The findings from our portfolio analysis suggest that GxE studies are concentrated in specific areas. There is room for investments in other aspects of GxE research, including, but not limited to developing alternative approaches to exposure assessment, broadening the spectrum of cancer types investigated, and performing GxE within GWAS.
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ABSTRACT: Cancer risk is determined by a complex interplay of genetic and environmental factors. Genome-wide association studies (GWAS) have identified hundreds of common (minor allele frequency [MAF] > 0.05) and less common (0.01 < MAF < 0.05) genetic variants associated with cancer. The marginal effects of most of these variants have been small (odds ratios: 1.1-1.4). There remain unanswered questions on how best to incorporate the joint effects of genes and environment, including gene-environment (G × E) interactions, into epidemiologic studies of cancer. To help address these questions, and to better inform research priorities and allocation of resources, the National Cancer Institute sponsored a "Gene-Environment Think Tank" on January 10-11, 2012. The objective of the Think Tank was to facilitate discussions on (1) the state of the science, (2) the goals of G × E interaction studies in cancer epidemiology, and (3) opportunities for developing novel study designs and analysis tools. This report summarizes the Think Tank discussion, with a focus on contemporary approaches to the analysis of G × E interactions. Selecting the appropriate methods requires first identifying the relevant scientific question and rationale, with an important distinction made between analyses aiming to characterize the joint effects of putative or established genetic and environmental factors and analyses aiming to discover novel risk factors or novel interaction effects. Other discussion items include measurement error, statistical power, significance, and replication. Additional designs, exposure assessments, and analytical approaches need to be considered as we move from the current small number of success stories to a fuller understanding of the interplay of genetic and environmental factors.
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ABSTRACT: Results: Overall screening rates for CRC did not statistically significantly differ between the usual care (35.7%) and GERA (33.1%) groups. After adjustment for baseline participant factors, the odds ratio for screening completion for GERA versus usual care was 0.88 (95% CI, 0.64 to 1.22). Within the GERA group, screening rates did not significantly differ between average-risk (38.1%) and elevated-risk (26.9%) participants. Odds ratios for elevated- versus average-risk participants remained nonsignificant after adjustment for covariates (odds ratio, 0.75 [CI, 0.39 to 1.42]). Limitation: Only 1 personalized genetic and environmental interaction and 1 health behavior (CRC screening) were assessed.
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ABSTRACT: Little is known about the impact of genetic and environmental risk assessment (GERA) feedback on colorectal cancer (CRC) screening. In a recently completed randomized trial, primary care patients received GERA feedback based on a blood test for genetic polymorphisms and serum folate level (GERA Group) versus usual care (Control Group). Subsequently, participants were offered CRC screening. Among participants who received GERA feedback, being at elevated risk was negatively associated with prospective CRC screening adherence. Secondary analyses of data from this study were performed to identify independent predictors of adherence among participants who received GERA feedback. We obtained baseline survey, follow-up survey, and endpoint medical records data on sociodemographic background, knowledge, psychosocial characteristics, risk status, and adherence for 285 GERA Group participants. Univariate and multivariable analyses were performed to identify predictors of CRC screening adherence. Following a 6-month outcomes observation period, we also conducted two focus groups with GERA Group participants to assess their perceptions of GERA risk feedback and screening. Content analyses of focus group data were evaluated to gain insights into participant response to risk feedback. Overall, half of GERA Group participants adhered to screening within 6 months after randomization. Multivariable analyses showed a statistically significant interaction between race and GERA feedback status relative to screening adherence (p = 0.043). Among participants who received average risk feedback, adherence was comparable among whites (49.7 %) and nonwhites (54.1 %); however, among those at elevated risk, adherence was substantially higher among whites (66.7 %) compared to nonwhites (33.3 %). Focus group findings suggest that whites were more likely than nonwhites to view elevated risk feedback as a prompt to screen. In response to receiving elevated risk feedback, nonwhites were more likely than whites to report feeling anxiety about the likelihood of being diagnosed with CRC. Further research is needed to explore race-related CRC screening differences in response to GERA feedback.
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