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Red meat linked to increased cancer risk in some people

According to a news release from the University of Southern California, researchers found that a common genetic variant that impacts one in three people significantly raises the risk of colorectal cancer from the consumption of red meat and processed meat.

The study also shows another specific genetic variation that seems to change whether eating more vegetables, fruits and fiber actually decreases your colorectal cancer risk.

“Diet is a modifiable risk factor for colorectal cancer. Our study is the first to understand whether some individuals are at higher or lower risk based on their genomic profile. This information can help us better understand the biology and maybe in the future lead to targeted prevention strategies,” said lead author Jane Figueiredo, Assistant Professor of Preventive Medicine at the Keck School of Medicine of USC.

“But we are not saying that if you don’t have the genetic variant that you should eat all the red meat you’d like,” Figueiredo noted. “People with the genetic variant allele have an even higher increased risk of colorectal cancer if they consume high levels of processed meat, but the baseline risk associated with meat is already pretty bad.”

According to senior author Ulrike Peters, of the Fred Hutchinson Cancer Research Center’s Public Health Sciences Division, how our genetic variations change the impacts of diet on disease has not yet been thoroughly examined.

The researchers looked through the more than 2.7 million genetic sequences for interactions with consumption of red meat. The research took into consideration 9,287 patients with colorectal cancer and 9,117 individuals without cancer.

The risk of colorectal cancer linked to processed meat was much higher among people with the genetic variant rs4143094. This variant is positioned on the same chromosome 10 region that includes GATA3, a transcription factor gene previously associated with several types of cancer. The transcription factor encoded by this gene typically has a role in the immune system, but carries this genetic variant in approximately 36 percent of the population.

The researchers think that the metabolism of processed meat may bolster an immunological or inflammatory response that may activate tumor formation. The GATA3 transcription factor typically would assist with the containment of the immunological or inflammatory response. However, if the GATA3 gene region has a genetic variant, it may encode a dysregulated transcription factor that affects it ability to hold the response in check.

But other genetic variants may be helpful: One chromosome 8, another diet-gene interaction was discovered in variant rs1269486. For people with this variant, consuming fruit and veggies may be even more beneficial for lowering colorectal cancer risk.

The NIH-funded Genetics and Epidemiology of Colorectal Cancer Consortium (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,” Peters noted.

Colorectal cancer is the third leading cause of cancer death in both men and women across most racial groups.

“Colorectal cancer is a disease that is strongly influenced by certain types of diets,” Figueiredo added. “We’re showing the biological underpinnings of these correlations, and understand whether genetic variation may make some people more or less susceptible to certain carcinogens in food, which may have future important implications for prevention and population health.”

The study’s findings were presented at the annual American Society of Human Genetics 2013 meeting.