Fusobacterium and Escherichia: models of colorectal cancer driven by microbiota and the utility of microbiota in colorectal cancer screening

Abstract

Intestinal microbiota has emerging roles in the development of colorectal cancer (CRC). Intestinal dysbiosis, with altered levels of specific bacteria, is consistently seen in CRC. The heart of the debate lies in whether these bacteria are a cause or consequence of CRC. Two bacteria in particular, Fusobacterium nucleatum and Escherichia coli, have consistently been associated with CRC. This review will examine evidence supporting oncogenic roles of F. nucleatum and E. coli. The proposed mechanisms of tumor formation follow two models: bacterial induced chronic inflammation leads to cell proliferation and tumor formation and virulence factors directly induce tumor formation. This review will further examine the potential for microbiota as biomarkers in CRC, with a focus on F. nucleatum.

Keywords:

• biomarker
• colorectal cancer
• escherichia
• fusobacterium
• inflammation

Financial & competing interests disclosure

The manuscript was supported by 863 Program Grant China (2012AA02A506), 973 Program Grant China (2013CB531401), Shenzhen Technology and Innovation Project Fund (JSGG20130412171021059). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Emerging studies have implicated intestinal microbiota in the development of colorectal cancer.

• Colorectal cancer patients display disrupted microbial homeostasis.

• The bacteria Fusobacterium nucleatum and Escherichia coli have consistently been associated with colorectal cancer.

• Bacterial induced chronic inflammation may lead to cell proliferation and tumor formation.

• The virulence factors of bacteria can directly induce tumor formation.

• Bacteria and its products act as a biomarker for colorectal cancer patients.