Dr Mario Moisés Álvarez, from the

Monterrey Institute of Technology and

Higher Education (Mexico), was the winner

of the 2019 Biocodex national grant in

Mexico, for his study of the interaction

between the gut microbiota and the

tumorous cells involved in colorectal cancer.

His team studies how certain organisms in

our microbiota inhibit cancerous processes.

This organ-on-chip system lets us analyze

two compartments connected to each

other via micro-channels: one contains

bacteria characteristic of the gut microbiota

of humans, and the other recreates a

cancerous process on the host, by keeping

a small colorectal tumor in culture.

The aim? To understand how the

molecules produced by these digestive

tract bacteria affect the growth of the

tumor. The knowledge gained could help us

fight colorectal cancer more effectively in

the future

(13)

.

A PREDISPOSING FACTOR OR CAUSE OF CANCER

Bearing in mind that breast cancer is the most common

cancer among women a new hypothesis suggests

that microbiota might be involved Several studies have

highlighted the direct and indirect role of microbiota in

the development of this type of cancer

On one hand it has been proven that the risk of breast

cancer depends partly on the type and ratio of estrogen

and the metabolites produced by the gut microbiota

On the other hand some researchers have discovered that

the composition of microbiota present in the breast tissue

varies according to the fact women suffer or not from

breast cancer Other researchers have shown that the

composition of the gut microbiota varies depending on

the cancer stage Could the two be connected

Investigations are underway

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USING IT AS A BIOMARKER

Microbiota could be a welcome addition to oncologists’

treatment options. A Japanese team has begun using

microbiota as a non-invasive marker of high-grade

prostate cancer. The researchers observed that three

bacterial groups were present in larger numbers in patients

presenting with high-grade prostate cancer

(11)

. These

results need to be confirmed on a wider scale before they

can be transposed into routine clinical practice.

IMPROVING TREATMENTS

Whether the aim is to improve the efficacy of

treatments or limit their side effects, interactions

between microbiota and cancer treatments are the

focus of many research programs, some of which

have been published in prestigious journals such as

Nature Medicine.

The most striking illustration to date is the use of

immunotherapy to treat non-small cell lung cancer,

the efficacy of which may be influenced by the

abundance of Akkermansia muciniphila (Akk) in the

gut microbiota.

A French team of researchers is assessing the

impact of administering this probiotic bacteria (Akk)

on treatment efficacy among patients with advanced

lung cancer.

Other bacteria, such as Faecalibacterium prausnitzii,

may also play a role in treatment response. There

remains a lot to discover; microbiota could be a

criterion for guiding therapeutic choices

(10)

.

THE EXPERT

TO WATCH

Mario Moisés Álvarez

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