More on bugs and cancer

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 1^st:

Researchers identify bacteria tied to esophageal cancer. http://tinyurl.com/y7hrksco