Scientists have known for nearly a decade that eating processed meat can increase the risk of colon cancer. Now a new study shows that risk is even higher for people who’ve inherited a common gene variant.
The variant, which is carried by one in three people, upped the risk substantially, researchers reported in the study published in PLOS Genetics Thursday.
Among those who consumed processed meats like sausage, salami, and bacon, there was about a two-fold increased risk of colorectal cancer when the genetic variant was present, said Dr. Ulrike (Riki) Peters, a member of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center and a research professor at the University of Washington.
Still, Peters said, “we’re still very early on in understanding these links between genetics and dietary factors and how they impact the risk for colorectal cancer and other diseases.”
For the new study, Peters and her colleagues systematically combed through 2.7 million genetic variants in 18,000 people from the United States, Canada, Australia and Europe. Genetic profiles and eating habits of 9,287 colon cancer patients were compared to those of 9,117 individuals without cancer.
As it turns out, the genetic variant that bumped up colon cancer risk in processed meat eaters is in the same region where genetic variant are located that have been linked with prostate and breast cancer, Peters said.
Scientists don’t yet know the underlying function of the genetic variant in question, Peters said. That’s something for future studies.
Still, the researchers noted that the variant lies near a region that is involved with the immune system. So, it’s possible that processed meat may trigger some kind of inflammatory or immunological response, they suggested.
“Our results suggest that genetic variants may interact with diet and in combination affect colorectal cancer risk, which may have important implications in the future for personalized cancer care and provide novel insights into prevention strategies,” the study authors wrote.
Peters and her colleagues chose to look at colorectal cancer because other research has shown that its development depends both on genes and environment.
Some cancers are more heritable, while others seem to be more environmentally related, Peters said. “Colorectal cancer is in the middle,” she added. “It’s a complex disease. So it’s in most cases not just one factor that determines whether a person developes cancer.”
Besides, Peters said, “there are a lot of known environmental risk factors, such as other dietry factors, obesity or smoking. So it’s important to study interactions between the environment and genes.”
The good news is that dietary modifications may benefit everyone – whether they carry the genetic variant or not.
Besides, she said, “reducing the intake of processed meat overall is preventive for several diseases.”
Solid tumors, such as those of the colon, are the focus of Solid Tumor Translational Research, a network comprised of Fred Hutchinson Cancer Research Center, UW Medicine and Seattle Cancer Care Alliance. STTR is bridging laboratory sciences and patient care to provide the most precise treatment options for patients with solid tumor cancers.