A new study has linked Salmonella exposure to a heightened risk of colon cancer. Led by Jun Sun, Ph.D. from the University of Illinois Chicago, researchers observed human colon cancer tissue samples and animal models, finding that exposure to Salmonella may be linked with instances of colon cancer that develop earlier and have larger tumor growth.  

The present study builds on a prior, Netherlands-based retrospective study of colon cancer patients that found Salmonella antibodies to be present in tissue samples from people who had poor oncological outcomes. Using the same Salmonella strains isolated from the tissue samples, Dr. Sun and her based team observed mice with colon cancer after exposure to the pathogen.

The researchers led by Dr. Sun observed accelerated tumor growth and larger tumors in mice with Salmonella exposure. Additionally, the results indicated an increased level of Salmonella translocated to the cancer tumors.

Dr. Sun’s collaborators in the Netherlands also studied Salmonella’s effect on tumor growth in vitro, combining human cancer cells and pre-cancer cells with the pathogen. After measuring the tumor for any growth or changes, the Dutch scientists saw that even one infection by Salmonella can cause oncogenic transformation, and that each subsequent Salmonella infection may exponentially increase the rate of cell transformation.

According to Dr. Sun, during infection, Salmonella takes over essential host signaling pathways, and such molecular manipulations may cause oncogenic transformation. The present study indicates that more research is needed into the connection between Salmonella exposure and colon cancer risk in the U.S., and exemplifies the importance of food safety in mitigating foodborne Salmonella.

Overall, the mouse and tissue culture experiments show that Salmonella infection may have a chronic effect that accelerates cancerous tumor growth. Dr. Sun expressed the need for further studies on Salmonella exposure as an environmental risk factor for chronic diseases, such as colon cancer.

Dr. Sun’s Dutch counterparts for the present study are associated with Leiden University Medical Center, the National Institute for Public Health and the Environment, and Utrecht University, which are all located in the Netherlands.