Red and processed meat consumption was significantly associated with colorectal cancer risk in patients who had a common gene mutation, researchers found.
In patients with the genetic variant rs4143094, eating red meats or processed meats was associated with an increased risk of colorectal cancer (OR 1.15 and 1.11, respectively, P<0.001 for both), while consumption of vegetables, fruit, or fiber was associated with a protective effect (OR 0.91, 0.93, and 0.91, respectively, P<0.001 for all), according to Jane Figueiredo, PhD, of the University of Southern California in Los Angeles, and colleagues.
The variant is located on the same 10 chromosome region as GATA3, 'a transcription factor gene previously linked to several forms of cancer' that normally plays a role in the immune system, Figueiredo said in a presentation at the Genetics and Epidemiology of Colorectal Cancer Consortium in Boston, Mass.
'If replicated, our findings have a relevant public health significance because diet is a modifiable risk factor for colorectal cancer,' noted Figueiredo in a statement accompanying the study.
Prior research has supported several methods for predicting or testing for colorectal cancer, including a risk score index of phenotype characteristics, regular primary care physician visits, and various forms of screening such as colonoscopy or fecal occult-blood testing.
A study in September 2013 showed, in a small patient sample, that a genetic test for two gene mutations was able to parse cancer tissue, adenomas, and serrated lesions from large amounts of normal DNA.
For the current study, the authors conducted a case-control analysis of 9,287 patients with colorectal cancer and 9,117 controls to analyze interactions between genetic factors and participants' diets on risks for colorectal cancer.
Data were collected on an individual level through 10 observational studies and used to form a logistic regression for gene-diet interactions with colorectal cancer, based on quartile increment of intake.
The investigators also used a 'cocktail method that involves a screening step based on marginal associated and gene-diet correlations and a testing step for gene-by-diet interactions, while correcting for multiple testing using weight hypothesis testing.'
The cocktail analysis showed additional support for the interaction between gene variants 'at the known locus 8q23.3/EIF3H, UTP23, and vegetable intake,' which was significant at P-screen<0.001, and P-interaction and -alpha<0.01.
Possible mechanisms of action include a gut microbiome that differs by dietary habits, or it may be possible that processed meat triggers a pro-tumorigenic inflammatory or immunological response, the authors suggested.
'These genetic loci have interesting biological significance, given their location in the genome, and further functional analyses are required,' they concluded, adding that these findings added additional support for modifiable risks for colorectal cancer.
The authors declared no conflicts of interest.
Primary source: Genetics and Epidemiology of Colorectal Cancer Consortium Source reference: Figueiredo J, et al 'Genome-wide analysis highlights gene interaction with processed meat and vegetable intake for colorectal cancer risk' GECCO 2013.
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