Why should we need the gut microbiota to respond to cancer therapies?

Cyclophosphamide, one of the most efficient tumoricidal, antiangiogenic, and immunostimulatory drugs employed to date mediates part of its effects through intestinal bacteria, against which the host becomes immunized during treatment. Our recent work suggests that anti-commensal effector pT_H17 and memory T_H1 CD4⁺ T-cell responses are indispensable for optimal anticancer effects as mediated by cyclophosphamide.