More than 100 trillion bacteria naturally inhabit every person's body; they are collectively referred to as the microbiome. Fusobacterium nucleatum is one such strain but it reduced the survival of patients with esophageal cancer.
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.
"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 Baba.
Baba and colleagues collected 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 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 esophageal cancer.
The researchers 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.
"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."