A publication in the December
issue of Cancer Research points towards another complicated relationship
between bacteria and cancer risk.
A group headed by researchers at
the Perlmutter Cancer Center (NYU Langone) looked at data gathered from more
than 120,000 subjects already enrolled in an ongoing NCI-sponsored study
looking at the link between nutrition and certain cancers.
The presence of a mouth-dwelling
bacterium, Tannerella forsythia, was associated with a 21% increase in the risk
of oesophageal adenocarcinoma after adjusting for other known risk factors
including smoking, drinking and body mass index.
In contrast, the presence of various
Streptococcus and Neisseria species was associated with a
24% decrease in cancer risk. The presence of Porphyromonas gingivalis, a bacterium associated with gum disease,
appeared to correlate with a higher risk of another form oesophageal cancer, oesophageal squamous cell carcinoma.
How mouth bacteria influence
oesophageal cancer risk is not clear. An association between poor oral health
and a higher risk of oesophageal cancer has been suggested in epidemiological
studies. Neisseria are capable of partially detoxifying tobacco smoke, with
lower numbers of Neisseria found in
the mouths of smokers than in non-smokers.
Bacterial metabolism analysis hinted at an increase in oesophageal adenocarcinoma
risk associated with some pathways but a lower risk with others. Certain
metabolites produced by Neisseria sp correlated
with the observed protective effect.
While cause and effect remains
elusive, it’s possible that analysis of oral flora might eventually serve as a
useful marker for oesophageal cancer risk and that manipulation of the oral
flora could reduce occurrence in those already at higher risk through other
behaviours. What’s clear is that “local”
microbiomes, whether mouth or gut, can have a profound effect on distant
organs.
Oral microbiome composition
reflects prospective risk for esophageal cancers. Peters, BA et al. Cancer Res 2017;77:6777-6787.
A NYU press office release was
published online in December 1st:
Researchers identify bacteria
tied to esophageal cancer. http://tinyurl.com/y7hrksco
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