Among Japanese patients with esophageal cancer, those whose cancer tested positive for DNA from the bacterium Fusobacterium nucleatum had shorter cancer-specific survival compared with those whose cancer had no DNA from the bacterium.

This research was published in Clinical Cancer Research, a journal of the American Association for Cancer Research.

More than 100 trillion bacteria naturally inhabit every person’s body; they are collectively referred to as the microbiome.

“The gut microbiome has recently been shown to play an important role in health, as well as in diseases such as obesity, inflammatory bowel disease, diabetes, nonalcoholic fatty liver disease, and several types of cancers,” said Hideo Baba, MD, PhD, a professor in the Department of Gastroenterological Surgery in the Graduate School of Medical Sciences at Kumamoto University, Japan. “We set out to investigate whether F. nucleatum, which is part of many people’s oral microbiome, is associated with oesophageal cancer development and/or progression.”

Baba and colleagues collected oesophageal cancer tissue samples from 325 consecutive patients who were having the cancer surgically removed at Kumamoto University Hospital from April 2005 to June 2013 and tested them for the presence of F. nucleatum DNA.

Patients were followed until January 31, 2016, or death.

During this time, there were 75 deaths attributable to oesophageal cancer.

The researchers detected F. nucleatum DNA in 23 percent of the oesophageal cancer tissue samples they tested.

The presence of F. nucleatum DNA was associated with shorter survival. Specifically, after controlling for factors associated with survival, such as age, tobacco use, and tumour stage, patients with tumours positive for F. nucleatum DNA were significantly more likely to have died as a result of oesophageal cancer.

“Our findings suggest that testing for the presence of F. nucleatum DNA in oesophageal cancer tissue could provide a biomarker of prognosis,” said Baba. “If they are replicated in a large, international, multi-institutional study, such testing could provide physicians with important information to consider while deciding how best to manage the care of a patient with oesophageal cancer. In addition, the data suggest that therapeutic targeting of F. nucleatum could be a potential new approach to suppress the development and growth of oesophageal cancer.

“It is important to note that our data provide no insight into whether F. nucleatum causes oesophageal cancer,” added Baba. “However, this is something we are hoping to study in the future.”

According to Baba, the main limitation of the study is that this is a single-institution study.

Because the component bacteria of a person’s microbiome differ according to numerous factors, including age, place of residence, food consumed, and race, these data cannot be generalised to all individuals unless they are confirmed in a large, international, multi-institutional study.

Source: Clinical Cancer Research