Salmonella infection acts as an environmental risk factor for human colon cancer.

Emerging evidence has demonstrated that perturbations of host-microbial interactions by pathogens can lead to an altered microenvironment that promotes tumorigenesis. A recent study provides new evidence and mechanisms on how repetitive exposure to non-Typhoidal Salmonella (NTS) increases the risk for colon cancer. This study integrated a serological and epidemiological approach with both in vivo and in vitro analyses, showed that the magnitude of exposure to NTS is associated with colonic tumorigenesis. In vivo exposure to repetitive low doses of NTS led to colonic tumors similar as a single high NTS dose in mice. Repetitive NTS infections significantly increase the proliferation of transformed cells in tissue cultures. The research results open new possibilities for the diagnosis, prevention, and treatment of colon cancer. The unanswered questions remain, including validation of the current findings in other cohorts, differences in lifestyle, and changes of gut microbiome after Salmonella infection. Salmonellae exposure can be limited by eating cooked meats and washing vegetables well. It is necessary to develop guidelines and criteria for screenings and follow-ups in people with exposure history to Salmonella and other cancer-associated pathogens.