Numerous
cancers have been linked to microorganisms. Warren et al. from British Columbia
Cancer Agency, Vancouver, Canada; investigated the relationship between gut
mucosal microbiome and colorectal cancer using genetic methods. The
investigation revealed an association between Fusobacterium species and
colorectal carcinoma in eleven patients. These investigators have extended
their studies with deeper sequencing of a much larger number (n = 130) of
colorectal carcinoma and matched normal control tissues.
The
new report has revealed differently abundant microbial genome sequence
signatures of significance in tumor samples, including those belonging to the
Fusobacterium, Campylobacter and Leptotrichia genera. These Gram-negative
anaerobes are typically considered to be oral bacteria. However, tumor isolates
for Fusobacterium and Campylobacter were genetically diverged from their oral
counterparts and carry potential virulence genes. They also observed that sequence
signatures from Fusobacterium co-occur with those from Leptotrichia and
Campylobacter and that Fusobacterium and Campylobacter strains isolated from
tumor tissue co-adhere in culture. A non-invasive assay to detect this
polymicrobial signature of colorectal carcinoma may have utility in screening
and risk assessment.
It remains unknown whether there is any etiological link
between microorganisms and colorectal carcinoma. Any such link could provide a
potential mode of intervention in the prevention of colonic cancer.
Fusobacterium necrophorum Gram stain
