PHILADELPHIA — 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, according to data 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,” said Hideo Baba, MD, PhD, a professor in the Department of Gastroenterological Surgery in the Graduate School of Medical Sciences at Kumamoto University, Japan. “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. We set out to investigate whether F. nucleatum, which is part of many people’s oral microbiome, is associated with esophageal cancer development and/or progression.”
Baba and colleagues detected F. nucleatum DNA in 23 percent of the esophageal 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 tumor stage, patients with tumors positive for F. nucleatum DNA were significantly more likely to have died as a result of esophageal cancer.
“Our findings suggest that testing for the presence of F. nucleatum DNA in esophageal 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 esophageal 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 esophageal cancer.
“It is important to note that our data provide no insight into whether F. nucleatum causes esophageal cancer,” added Baba. “However, this is something we are hoping to study in the future.”
The researchers generated the data by collecting esophageal 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 testing 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 esophageal cancer.
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 generalized to all individuals unless they are confirmed in a large, international, multi-institutional study.
The study was funded in part by SGH Foundation. Baba declares no conflicts of interest.