October 24, 2013
Gene-Diet Interaction Explains Link Between Meat And Colorectal Cancer
Lee Rannals for redOrbit.com - Your Universe Online
Researchers at the American Society of Human Genetics 2013 meeting in Boston say they have discovered an interaction that could explain the link between eating meat and colorectal cancer risk. The team said the newly discovered potential gene-diet interaction for colorectal cancer could shed light on the statistically significantly increased risk of the cancer that is associated with the consumption of red and processed meats.
"If replicated, our findings have a relevant public health significance because diet is a modifiable risk factor for colorectal cancer," said Jane Figueiredo, Assistant Professor of Preventive Medicine at the University of Southern California Keck School of Medicine. "It is conceivable that selected individuals at higher risk of colorectal cancer based on genomic profiling could be targeted for screening, diet modification and other prevention strategies.”
Scientists determined that lower colorectal cancer risk associated with vegetable, fruit and fiber intake was also linked to genetic variants. Ulrike Peters, a Member of the Fred Hutchinson Cancer Research Center's Public Health Sciences Division who headed the study, said the team’s research represents an important new insight into disease development.
This is the first colorectal cancer investigation with the statistical power to identify gene-dietary interactions across the genome of a large population of individuals. The study included 9,287 patients with colorectal cancer and a control group of 9,117 individuals without cancer, all of whom were participants in the 10 Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) observational studies.
Scientists searched 2.7 million gene variants to identify those that are associated with the consumption of red meat and processed meat as well as fruits and vegetables. The genetic sequences and information about the participants' medical history and diet are stored in the GECCO database.
The team found a significant interaction between the genetic variant rs4143094 and processed meat consumption. This variant can be found on the same chromosome 10 region that includes a transcription factor gene previously linked to several forms of cancer. They also found a statistically significant diet-gene interaction in another variant located on chromosome 8, which was associated with a reduced risk of colorectal cancer.
Researchers believe that digestion of processed meats may promote an immunological or inflammatory response that triggers tumor development. The transcription factor gene on chromosome 10 normally helps suppress the immunological or inflammatory response, but instead it contains a mutation that could encode a dysregulated transcription factor that impacts its ability to suppress the response.
Peters said that in addition to uncovering a novel gene-diet interaction for colorectal cancer, the study may have important implications for understanding the underlying causes and biological pathways of cancer.
"Our study highlights two genetic regions that are biologically interesting in cancer," she said. "These genetic loci may have interesting biological significance given their location in the genome, and further functional analyses are required.”
The team will continue to investigate gene-diet interactions through independent studies on a well-characterized large cohort of European colorectal cancer patients.
"GECCO aims to continue to discover additional colorectal cancer-related variants by investigating how genetic variants are modified by other environmental and lifestyle risk factors, including biomarkers as well as how they influence patient treatment response and survival," Dr. Peters said.