New
insights about young-onset CRC tumour-related bacteria could lead to new
diagnostic markers and therapeutic targets.
Researchers
from the Cleveland Clinic have identified changes in tumour-related bacteria,
which have revealed possible new strategies to tackle the increase of
young-onset colorectal cancer (CRC), which refers to CRC incidence in patients
under 50 years old.
CRC
is one of the leading causes of cancer related mortality worldwide, with some
of its risk factors being obesity, red meat consumption, alcohol and tobacco.
Despite this condition being easy to surgically treat and target with
chemotherapy following the operation, it has a five-year survival rate.
Although
the introduction of screening colonoscopy has resulted in the prevention and
decrease in overall incidence of CRC since the early 1990’s, the incidence of
CRC in young patients has continued to steadily increase annually. Moreover,
younger CRC patients have been shown to present with more advanced stages of
the disease. In young-onset CRC, hereditary CRC syndromes only explain the
minority of cases, and there is evidence to suggest that young-onset CRC has a
different molecular profile compared to late-onset CRC.
Cleveland
Clinic oncologist Dr Alok Khorana, the primary investigator of the new study,
explained: “The unexplained rise of young-onset colorectal cancer is of great
concern…Our team discovered that bacteria were more abundant and
compositionally distinct in tumours from young-onset patients.”
Gene sequencing
The
team utilised gene sequencing technology to compare tissue samples taken from
136 young-onset colorectal cancer patients with 140 average-age patients with
the disease. From this, they found unique tumour-related bacteria in the
younger cohort, who were more likely to have left-sided, rectal and advanced
stage tumours.
The
key microbes associated with the young-onset cancers included Akkermansia and
Bacteroides. Average-onset tumours showed a greater abundance of Bacillus,
Staphylococcus, Listeria, Enterococcus, Pseudomonas, Fusobacterium and
Escherichia/Shigella. Markedly, except in average-onset tumours, Fusobacterium
was scarce in all specimens.
Dr
Shimoli Barot of the Cleveland Clinic Cancer Institute commented: “By detailing
this microbial signature of young-onset disease, we can look toward new
screening biomarkers and drugs targeting related bacteria.”
The
unique behaviours of the Akkermansia and Bacteroides genera in young-onset CRC
provides a significant direction for further investigation. Dr Naseer Sangwan
of the Cleveland Clinic Lerner Research Institute concluded: “Further research
is needed into how lifestyle factors such as diet, medications and obesity may
impact gut bacteria and contribute to young-onset colon cancers.”
This
study was published in eBioMedicine.
World Journal of Case Reports and Clinical Images (ISSN 2835-1568)
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