“Ultimately, we concluded, cancer immunotherapy passes the test. It does
so because this year, clinical trials have cemented its potential in
patients and swayed even the sceptics. The field of cancer immunotherapy
hums with stories of lives extended — the woman with a grapefruit-size
tumour in her lung from melanoma, alive and healthy 13 years later; the
6-year-old near death from leukaemia, now in third grade and in
remission; the man with metastatic kidney cancer whose disease continued
fading away even after treatment stopped,” notes a paper published
recently in the journal that ranked the top 10 science breakthroughs of
2013.
The cancer research community experienced a sea change in 2013 as a
strategy, decades in the making, finally cemented its potential.
Promising results emerged from clinical trials of cancer immunotherapy,
in which treatments target the body's immune system rather than tumours
directly. The new treatments push T cells and other immune cells to
combat cancer — and the editors of believe that such approaches are now
displaying enough promise to top their list of the year's most important
scientific breakthroughs. Though the ultimate impact on the disease is
not known, results so far have been highlighting its success.
This annual list of groundbreaking scientific achievements, selected by
and its international nonprofit publisher, AAAS, also includes major
breakthroughs in solar cell technologies, genome-editing techniques and
vaccine design strategies, to name a few.
“This year there was no mistaking the immense promise of cancer
immunotherapy,” Tim Appenzeller, chief news editor of the journal saidin
a press release by the American Association for the Advancement of
Science (AAAS). “So far, this strategy of harnessing the immune system
to attack tumours works only for some cancers and a few patients, so
it's important not to overstate the immediate benefits. But many cancer
specialists are convinced that they are seeing the birth of an important
new paradigm for cancer treatment.”
Many of today's advances in cancer immunotherapy revolve around CTLA-4
(cytotoxic T-lymphocyte antigen 4) — a receptor on T cells that was
discovered in 1987. “The early steps were taken by French cancer
immunologist James Allison, now at the University of Texas, MD Anderson
Cancer Center in Houston. CTLA-4 prevented the T cells from attacking
invaders with their full force.
In 1996, James Allison showed that blocking CTLA-4 in mice could unleash
T cells against tumour cells in the animals that finally “erased
tumours in mice.”
In the meantime, Japanese researchers identified another “brake” on T
cells known as PD-1. Clinical trials involving this receptor began in
2006, and preliminary results in small groups of patients appear to be
promising.
Another area of interest involves genetically modifying T cells to make
them target tumours. In 2011, this strategy, which was known as chimeric
antigen therapy, or CAR therapy, electrified the cancer research field,
and it is now the subject of numerous clinical trials, particularly in
blood cancers.
Accordingly, many pharmaceutical companies that wanted nothing to do
with immunotherapy several years ago are now investing heavily, the
release noted.
There is still plenty of uncertainty regarding how many patients will
benefit from these therapies, most of which remain experimental — and
for which forms of cancer they will work best, the release noted.
Scientists are busy trying to identify biomarkers that might offer
answers, and thinking of ways to make treatments more potent. But a new
chapter in cancer research and treatment has begun. The journal’s list
of nine other groundbreaking scientific achievements from the past year
follows.
CRISPR: Akin to the discovery of the microscope in the 1920 that
“touched off a revolution in surgical procedures,” the discovery of a
bacterial protein — Cas9 — gives “researchers the equivalent of a
molecular surgery kit for routinely disabling, activating, or changing
genes,” the paper notes.
Though CRISPR, the gene-editing technique was discovered in bacteria,
researchers use it as a scalpel for surgery on individual genes. Its
popularity soared this year — with over 50 publications in 10 months —
as more than a dozen teams of researchers used it to manipulate the
genomes of various plant, animal and human cells.
Cloning human embryos: After years of failure, researchers were
able to derive stem cells from cloned human embryos this year.
Scientists were able to clone sheep, mice, pigs, dogs and other animals,
but human cells proved really tricky.
But in 2007, researchers at the Oregon National Primate Research Center
in Beaverton succeeded in cloning monkey embryos and extract embryonic
stem cells. In the process they realised that caffeine plays an
important role in the process, stabilizing key molecules in delicate
human egg cells.
CLARITY: This imaging technique, which renders brain tissue
transparent by “by removing the fatty, light-scattering lipid molecules
that form cellular membranes.” The lipids are replaced with molecules of
“clear gel” but all neurons (as well as other brain cells) are left
intact and on full display. This has changed the way researchers look at
this intricate organ in 2013.
According to the paper, researchers say the “advance could speed up by
100-fold tasks such as counting all the neurons in a given brain region
and could make traditional methods of imaging post-mortem brain tissue
irrelevant.” Currently, the technique is limited to small amounts of
tissue.
Mini-organs: Researchers made remarkable progress growing mini
human-like “organoids” in vitro this year. These included liver buds,
mini-kidneys and tiny brains. miniaturized human organs may prove to be
much better models of human disease than animals.
If it is a challenge to “coax stem cells to grow into specific tissues”
prodding pluripotent stem cells to develop into organized structures has
been nearly impossible. Not any more. Researchers in spectacular style
were able to grow a variety of “organoids” in the lab — liver buds,
mini-kidneys, and, most remarkably, rudimentary human brains.
Cosmic rays traced to supernova remnants: Although originally
detected 100 years ago, scientists have not been sure where the
high-energy particles from outer space known as cosmic rays come from.
This year, they finally tied the rays to debris clouds left by
supernovae, or exploding stars.
Perovskite solar cells: A new generation of solar-cell materials,
cheaper and easier to produce than those in traditional silicon cells,
garnered plenty of attention this past year. Perovskite cells are not as
efficient as commercial solar cells yet, but they are improving very
quickly.
Structural biology guides vaccine design: This year, researchers
used the structure of an antibody to design an immunogen — the main
ingredient of a vaccine — for a childhood virus that hospitalizes
millions each year. It was the first time that structural biology led to
such a powerful tool for fighting disease.
Our microbes, our health: Research on the trillions of bacterial
cells that call the human body home made it clear how much these
microbes do for us. "Personalized" medicine will need to take these
microbial tenants into account in order to be effective.
Why we sleep: Studies with mice showed that the brain cleans
itself — by expanding channels between neurons and allowing more
cerebrospinal fluid to flow through — much more efficiently during
sleep. The finding suggests that restoration and repair are among the
primary purposes of catching Z's.
