Gut microbes—or a lack thereof—can significantly affect the efficacy of certain cancer therapies elsewhere in the body, according to two studies appearing in Science (November 21: 1, 2). Independent teams show in mouse models of cancer that gut microbes appear to modulate the host immune responses sparked by the anticancer drug cyclophosphamide, as well as by certain types of immunotherapy and chemotherapy. Both found that germ-free mice responded less well to tumor-targeting therapies than animals with rich gut microbiomes.
“Most of the time we think about the gut microbiome shaping the local environment. Now these papers are breaking the glass ceiling and going into extra-intestinal organs . . . and influencing activities of drugs,” said Christian Jobin, a professor of infectious diseases and pathology at the University of Florida who reviewed both studies, and was not involved in either. “That’s really quite unique.”…
