The microbiome as a risk factor and biomarker of oesophageal cancer

Oesophageal cancer is the eighth most common cancer worldwide (19th most common in Europe) with nearly 456,000 new cases diagnosed in 2012. It is well established that microbes can cause cancer. For example, H. pylori infection can lead to stomach cancer. For other cancers, such as colon cancer, there is a change in the population of bacteria (or microbiome) on colon tumors. We don't know yet if these bacteria cause or accelerate cancer. Remarkably, we have found that oral microbes may be linked with colon cancer, but we suspect the link may be more relevant and stronger with cancer of the lower oesophagus.

We can tell from a patient's colon cancer microbiome where the tumor is -left or right side; and to the type of immune response the patient mounted. This is important because it relates to clinical prognosis and the patient's survival chances. We also showed that the microbiome on colon polyps (benign growths that may become cancerous) is intermediate between that of tumors and healthy tissue. This suggests that microbiome changes reflect the changes in tissue pathology over time.

Both colon polyps and colon tumors have bacteria that come from the oral cavity, and we hypothesize. that the colon cancer microbiome comes from the oral cavity. A logical inference is that these oral bacteria are also associated with oesophageal cancer, a biologically aggressive disease with poor prognosis and whose incidence has been increasing in recent decades. In the proposed research, we will carry out a prospective study in 4 cities of the oesophageal microbiota from 160 subjects with oesophageal inflammation, precancerous condition such as Barrett's oesophagus, or cancer. We will determine if an altered microbiome is present, if it can be used as an early detection method, or even as a therapeutic target for oesophageal cancer.


Award Date
29 June 2017
Award Value
Principal Investigator
Professor Paul O'Toole
Host Institution
University College Cork
Investigator Led Projects