More Evidence Links One Bacterial Species to Colorectal Cancer

Anthony L. Komaroff, MD

Researchers have identified a bacterial protein that stimulates tumor proliferation.

In late 2011, two groups reported finding one particular bacterial species, Fusobacterium nucleatum, in human colorectal cancer (CRC; NEJM JW Gen Med Nov 3 2011). However, any mechanism by which it might cause cancer was unknown; these bacteria simply might have an affinity for colonizing tumors.

One of the original groups now reports that F. nucleatum stimulates growth of CRC cells. In addition, F. nucleatum contains a unique adhesion antigen (FadA) on its surface that binds to a particular receptor on CRC cells and stimulates both inflammation and carcinogenesis. FadA levels in CRC tissue were 10 to 100 times higher than those in normal colon tissue. A synthetic peptide that blocked the binding of FadA to CRC cells also blocked its ability to stimulate proliferation of those cells.

The second group studied mice that were genetically engineered to develop CRC at a high rate. When F. nucleatum was placed in the gut of these mice, the number of tumors increased greatly.

Citation(s):

Rubinstein MR et al. Fusobacterium nucleatum promotes colorectal carcinogenesis by modulating E-cadherin/β-catenin signaling via its FadA adhesin. Cell Host Microbe 2013 Aug 14; 14:195.

Kostic AD et al. Fusobacterium nucleatum potentiates intestinal tumorigenesis and modulates the tumor-immune microenvironment. Cell Host Microbe 2013 Aug 14; 14:207.