The Think Tank participants discussed several large studies that have tested for GxE interactions for GWAS identified loci. Most of these studies have not observed statistically significant interactions [Campa, et al. 2011; Hutter, et al. 2010; Milne, et al. 2010; Nickels, et al. 2013; Travis, et al. 2010], although one study did find evidence for a statistical interaction between genetic variants at 8q22.3 and vegetable consumption for risk of colorectal cancer [Hutter, et al. 2012], and another showed evidence for statistical interactions between LSP1 and parity, and CASP8 and alcohol consumption for risk of breast cancer [Nickels, et al. 2013]. Generally these studies have focused on the statistical significance of GxE interaction terms, rather than full characterization of joint effects. Concern was raised as to whether these studies adequately model the genetic and environmental factors [Prentice 2011]. Participants discussed several initial GEWIS studies of cancer phenotypes with null findings that have yet to be published. While there have been a small number of initial success stories where consideration of environmental factors or GxE interactions contributed to discovery of novel genetic
