By studying the links between bacteria and cancer , scientists one day hope to be able to tell a person what his or her cancer risk is based on the bacteria present in his or her body, said Jiyoung Ahn, an associate professor of epidemiology at the New York University School of Medicine. Perhaps more important, Ahn said, these bacteria and microbes, collectively called the microbiome , could give people information about what they can do to lower their risk.
http://www.topix.com/health/esophageal-cancer/2017/04/what-the-bacteria-in-your-mouth-may-reveal-about-your-cancer-risk?fromrss=1
What the Bacteria in Your Mouth May Reveal About Your Cancer Risk