Nongenetic Factors Appear to Influence Colorectal Cancer Development

Mice models demonstrating colorectal cancer development were influenced by nongenetic factors such as gut microbes.

Researchers at the Icahn School of Medicine at Mount Sinai have identified gut microbes that they believe trigger genetic mutations that cause healthy cells in the intestines to become malignant, according to a study published in The Journal of Experimental Medicine. The scientists, who used mice to test their theory, believe nongenetic factors contribute to the tumor growth.

Mice carrying polyp-causing mutations in specific areas of their intestines were treated with antibiotics to disrupt the microbes’ behavior. The antibiotic prevented the malignant polyps from forming, which leads the researchers to believe that bacteria are essential for tumor development in this model.

“The development of these intestinal neoplasms in the cecum is driven by the interplay between genetic changes in the host, an inflammatory response, and a host-specific microbiota,” the authors write.

While the researchers are still unsure what the potential cancer-causing bacteria is, the results of the study suggest colorectal cancer can be prevented in genetically predisposed individuals by removing specific types of gut bacteria.

“In addition to genetic changes, various lifestyle-related factors, such as obesity and diet, have been linked to colorectal cancer. Some of these lifestyle factors appear to affect the types of bacteria present in the gut,” Sergio Lira, MD, PhD, Director of the Immunology Institute at the Mount Sinai School of Medicine and lead researcher on the study, explained. “Ultimately, understanding the interplay between genetic mutations, gut microbes, and inflammation may lead to novel diagnostics and therapies for intestinal cancer.”