Scientists believe they have discovered a way
to "steer" the immune system to kill cancers.
Researchers at University College, London have
developed a way of finding unique markings
within a tumour - its "Achilles heel" - allowing the
body to target the disease.
But the personalised method, would be expensive and has not
yet been tried in patients.
Experts said the idea made sense but could be
more complicated in reality.
However, the researchers, whose work was
funded by Cancer Research UK, believe their
discovery could form the backbone of new
treatments and hope to test it in patients within
two years.
They believe by analysing the DNA, they'll be able
to develop bespoke treatment.
People have tried to steer the immune system to
kill tumours before, but cancer vaccines have
largely flopped.
One explanation is that they are training the
body's own defences to go after the wrong target.
The problem is cancers are not made up of
identical cells - they are a heavily mutated, genetic
mess and samples at different sites within a
tumour can look and behave very differently.
'Exciting'
They grow a bit like a tree with core "trunk"
mutations, but then mutations that branch off in
all directions. It is known as cancer heterogeneity.
The international study developed a way of
discovering the "trunk" mutations that change
antigens - the proteins that stick out from the
surface of cancer cells.
Professor Charles Swanton, from the UCL Cancer
Institute, added: "This is exciting. Now we can
prioritise and target tumour antigens that are
present in every cell - the Achilles heel of these
highly complex cancers.
"This is really fascinating and takes personalised
medicine to its absolute limit, where each patient
would have a unique, bespoke treatment."
There are two approaches being suggested for
targeting the trunk mutations.
The first is to develop cancer vaccines for each
patient that train the immune system to spot
them.
The second is to "fish" for immune cells that
already target those mutations and swell their
numbers in the lab, and then put them back into
the body.
'Early days'
Dr Marco Gerlinger, from the Institute of Cancer
Research, said: "This is a very important step and
makes us think about heterogeneity as a problem
and why this gives cancer this big advantage.
"Targeting trunk mutations makes sense from
many points of view, but it is early days and
whether it's that simple, I'm not entirely sure.
"Many cancers are not standing still but they keep
evolving constantly. These are moving targets
which makes it difficult to get them under control.
"Cancers that can change and evolve could lose
the initial antigen or maybe come up with
smokescreens of other good antigens so that the
immune system gets confused."
Some immunotherapy treatments work
spectacularly with some patients' cancer
disappearing entirely.
They take the brakes off the immune system,
freeing it up to fight cancer.
The researchers hope the combination of
removing the immune system's brakes and then
taking over the steering wheel, will save lives.
Professor Peter Johnson, from Cancer Research
UK, said: "This fascinating research gives us vital
clues about how to specifically tailor treatment
for a patient using their immune system."
'Elegant study'
Dr Stefan Symeonides, clinician scientist in
experimental cancer medicine at the University of
Edinburgh, said designing a personalised vaccine
was currently impractical, especially when a
patient needed treatment straight away.
But he added that the "very elegant" study did
provide a ground-breaking insight into current
immunotherapy drugs, which do not yet work for
most people.
"It's not just the number of antigens, it's how
many of the cancer cells have them," he said.
"This data will be quoted in discussions for years,
as we try to understand which patients benefit
from immunotherapy drugs, which ones don't,
and why, so we can improve those therapies."
No comments:
Post a Comment