In the year 2018, according to the World Health Organization, nearly 10 million people died of cancer.
When two patients have exactly the same cancer
at the same stage, it can spread through the
body with varying intensity.
With one person, it leads to death after just
a few months – while the other person survives
for several more years.
Why should this be?
In the past, oncologists focused on the cancer cells, and on the genetic mutations of those cells.
But more important, or at least just as important,
are the immune cells that surround the cancer.
Jérôme Galon is a Director of Research at
the prestigious Institut national de la santé,
or INSERM for short, in Paris.
When he started working there in the early
2000s, cancer researchers still assumed that
only the cells of the tumour were responsible
for how aggressively cancer proliferated through
a patient's body.
Galon, on the other hand, had completely different ideas – he believed that the patient's immune
system was the key factor.
The more effectively the immune cells
shown here in brown
fight the degenerated cancer
cells and destroy them,
the slower the growth of the tumour.
There’s an immunological monitoring system
designed to prevent the spread of cancer.
But if cancer has got a grip, and the immune
system is too weak, then it can’t control
the cancer any longer - and it spreads further
inside the organism.
To prove his theory, the Frenchman embarked
on an elaborate project.
He wanted to re-measure tumour tissue samples
from countless cancer patients, to find out
how many immune cells they contained.
The idea: A large number of immune cells inthe tumour tissue meant that the body was
subjecting the cancer to an all-out attack
– enabling the patient to live longer.
With our trials, we wanted to analyse the
complete micro-environment of the cancer – and
we really did examine all the immune cells inside the tumour.
Using a highly complex procedure, the researchers stained all the immune cells present in the tissue.
This created microscopic images showing the immune cells in the tumour tissue as brown dots.
With the help of the computer, these dots
could now be counted – and the researchers
found from one to 8000 immune cells per square millimetre!
An elaborate procedure – and the scientists
repeated it on more than 7000 patients
The first study was published 10 years ago.
So there was a very, very long period of research
before we got these results.
But Galon and his team had not yet proven
that the number of immune cells had any significance.
That’s why they asked the hospitals and
the doctors who had given them the tissue
samples to provide them with more information
about the patients.
They wanted to know whether patients whose
immune systems had a larger number of cells
fighting the cancer were actually living for
longer.
If so, that would be a major breakthrough
for Galon and his team.
I still clearly remember that precise moment
of discovery.
I was at home, analysing the statistical findings,
and suddenly, I noticed that the response
of the patient's immune system really did
play a key role.
The data made it quite clear:
the higher the number of immune cells, the better the life
expectancy.
A correlation that Galon decided to name the “Immunoscore".
Cancer patients with a high score have a life expectancy of up to 15 years.
Patients with a low score, in contrast, 
manage only 2 years.
That opened my eyes to the importance of the immune response to cancer.
We really celebrated after that – it’s
opened up a whole new era, the era of anti-cancer
immunity, which is now unfolding with immunotherapy.
The  discovery caused quite a sensation in professional
circles, because, for doctors, it makes a
lot of things easier:
Thanks to this achievement - which I hope
can be used on many types of cancer – we
doctors can understand patients and their
tumours far better, and as a result, we know
what kind of treatment they should be given.
Does chemotherapy or radiation treatment have
to begin right away?
Or can doctors still wait, because the immune
system is successfully fighting the cancer?
Doctors can now make decisions like these far more accurately
thanks to the Immunoscore.
In 2005, Galon filed a patent application
for the method;
In 2014, he founded the company
“HalioDX", which went on to market the approach worldwide.
The Immunoscore-related market
has been estimated at over 1 billion euros
per year;
and today the method is already
in use in 19 countries.
Why does cancer proliferate so aggressively
in one patient, while growing far more slowly
and sometimes even disappearing in another?
Galon and his team have indeed found an answer
to that mystery.
It’s an invention that will provide many
cancer patients with better treatment in the
future, in particular through novel immunotherapy
to reactivate their immune systems.
