Colon Cancer and Bacteria


Researchers at Harvard University and VHIO cancer Institute in Barcelona report that colon cancer may be caused by a specific bacteria, Fusobacterium nucleatum (Science, Nov 23, 2017). I believe this is breakthrough research that could lead to a potential cure for colon cancer and a Nobel Prize.

Known causes of cancers include genetic defects or mutations, toxins, and infections. For example, most cervical cancers are caused by infection with HPV viruses. Fusobacterium nucleatum can be found in normal human colon tissue, but is found in very high concentrations in colon cancer tissues. The researchers showed that this Fusobacterium:
• is found specifically in human colon cancer tissue,
• is found in colon cancer cells that have spread to the liver, and
• has been passed with the cancer cells repeatedly through multiple passages in animals and tissue cultures.
Treating colon cancer in mice with metronidazole (an antibiotic) reduces Fusobacterium load, cancer cell growth, and spread of the colon cancer to other tissues.

Further Evidence to Support a Bacterial Cause of Colon Cancer
Other studies show that having large amounts of Fusobacterium in colon cancer cells is associated with:
• reduced body defense against cancer such as less T-cell infiltration (JAMA Oncol, Aug 1, 2015;1(5):653–661),
• increased spread of the cancer (Annu Rev Microbiol, Sep 8, 2016;70:395–411), and
• earlier death from colon cancer (Cell, July 27, 2017;170(3):411–413).

What you eat determines which types of bacteria grow in your colon because the bacteria in your colon eat the same foods that you do. The highest load of Fusarium exists in the right side of the colon. Bacteria in the right side of your colon get all of their food from the same foods that you eat, while the bacteria in your left side of your colon get what is left over after the food is eaten by bacteria in the right side of your colon. This may explain why certain foods are associated with increased risk for colon cancer: red meat, processed meats, sugar-added foods and fried foods (JAMA Oncol, published online January 26, 2017; Oncol Rev, Feb 10, 2015;9(1):288; N Engl J Med. 1990;323:1664-72). Right-side colon cancer is far more common and far more likely to kill a person than left-side colon cancer. See my recent report on Colon Cancer, Gut Bacteria and Diet

• Colon cancer may be caused by a bacterium called Fusobacterium nucleatum that is common in human colons.
• This bacterium is found in large amounts in colon cancer tissue, travels with the colon cancer when it spreads to the liver, spreads to the liver in mice with colon cancer when the cancer metastasizes, and is passed in tissue cultures.
• The next step will be to show whether getting rid of Fusobacterium nucleatum can cure or prevent colon cancer.