Certain gut microbes work with a common cancer drug by boosting anti-tumour immune responses, making the therapy more effective in mice.

Laurence Zitvogel of the Gustave Roussy Cancer Campus in Villejuif, France, and his colleagues studied the effect of two species of bacteria on the action of the drug cyclophosphamide. When they gave antibiotic-treated mice the microbe Enterococcus hirae, they found that it made immune cells called T cells more active against specific tumour markers and caused intestinal immune cells to proliferate. Another bacterium, Barnesiella intestinihominis, drove immune cells to infiltrate tumours. In mice that lack a protein that restricts these species' growth, the cancer drug was nearly twice as effective at reducing tumour size than in normal animals.

The results suggest that gut bacteria could be used to optimize cancer therapies, the authors say.

Immunity http://doi.org/brmm (2016)