Manipulative Microbiomes

Gut bacteria control tumor growth via the mammalian immune system.

Jenny Rood
Apr 1, 2015

CANCER COMMAND: The microbiome (as puppeteer) affects the immune system’s influence on tumor growth, in tandem with inflammatory cytokines (dogs).ILLUSTRATION BY MELANIE R. RUTKOWSKI AND GRAPHIC DESIGN BY SUBTERRANEAN GRAFIX

EDITOR'S CHOICE IN CELL & MOLECULAR BIOLOGY

The paper
M.R. Rutkowski et al., “Microbially driven TLR5-dependent signaling governs distal malignant progression through tumor-promoting inflammation,” Cancer Cell, 27:27-40, 2015.

The polymorphism
The gut microbiome influences nonintestinal cancer progression, but the role of toll-like receptor 5 (TLR5), an immune system protein that recognizes commensal bacteria, was a mystery. As more than seven percent of people have nonfunctional TLR5, José Conejo-Garcia of the Wistar Institute in Philadelphia and colleagues explored how TLR5 impacts tumor growth.

The controller
In a mouse model of sarcoma, the researchers found that tumors grew much faster in wild-type mice than in TLR5-deficient ones. Wiping out the mice’s microbiomes diminished the disparity, indicating that TLR5’s tumor-promoting effects...