The risk of getting colorectal cancer from eating processed meat is significantly increased in 1 in 3 people who are carriers of a common gene variant, according to a new review published in PLOS Genetics.
Colorectal cancer is the third leading cause of cancer death in both men and women and across most ethnic-racial groups. It is influenced by a variety of factors, including genetic causes and lifestyle factors such as diet.
Previous studies have suggested that eating red or processed meat slightly increases risk of colorectal cancer, and that fruits, vegetables and fiber decrease risk.
Research has focused more recently on how common genetic variants might influence the relationship between certain dietary factors and colorectal cancer risk.
But these studies have mostly looked at the genetic variants called single nucleotide polymorphisms that are directly involved in metabolizing B-vitamins or key nutrients in fruit and vegetables.
The review analyzed 10 studies comprising 9,287 colorectal cancer cases and 9,117 controls. It examines more than 2.7 million common polymorphisms for how they interact with red meat, processed meat, fiber, fruit and vegetables, and how this affects colorectal cancer risk.
Interaction between processed meat and genetic variant 'rs4143094'
The researchers - whose work was sponsored by the National Institutes of Health-funded Genetics and Epidemiology of Colorectal Cancer Consortium and Colorectal Cancer Family Registry - detected a significant interaction between the genetic variant "rs4143094" and processed meat.
Fast facts about colorectal cancer
- Colorectal cancer usually starts in the glands lining the colon and rectum.
- Nearly all colorectal cancers begin as benign polyps, which slowly develop into cancer.
- Depending on the stage of the cancer, treatment may include surgery, chemotherapy or radiation therapy.
This variant is linked to a gene called GATA3 that has previously been linked to several forms of cancer and plays a role in the immune system.
Dr. Jane Figueiredo, of the Keck School of Medicine at the University of Southern California, says their findings represent a significant breakthrough in understanding how colorectal cancer risk is influenced by an individual's genomic profile:
"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."
Dr. Figueiredo believes that there may be further biological significance behind this interaction, due to the area of the genome that is affected, but acknowledges that further research is required.
"Our results, if replicated by other studies, may provide us with a greater understanding of the biology into colorectal carcinogenesis," adds Dr. Ulrike Peters of the Fred Hutchinson Cancer Research Center's Public Health Sciences Division.
"The possibility that genetic variants may modify an individual's risk for disease based on diet has not been thoroughly investigated but represents an important new insight into disease development," concludes Dr. Li Hsu, the lead statistician on the study.
Recently, Medical News Today reported on a study that found gut bacteria may sustain colorectal cancer by suppressing DNA repair.
Written by David McNamee