Cancer, it’s safe to say, really sucks.
We’ve been at war with the disease for years,
and every little breakthrough gets us closer
to better ways to treat it.
But just in the last couple of weeks, we’ve
taken two major steps toward a future where
every type of cancer has a cure.
First, leukemia took a significant hit last
week when the FDA approved the very first
gene therapy available in the US.
Gene therapy involves reprogramming cells
to add new genes or fix ones that aren’t
working the way they should.
It has a ton of potential for treating genetic
diseases, and researchers are also looking
into ways to use it to target the genes and
proteins involved in different types of cancers.
Now we’re finally starting to turn that
potential into reality.
As of last week, gene therapy was officially
approved to treat acute lymphoblastic leukemia.
Leukemia makes the production of white blood
cells, one of the most important parts of
your body’s immune system, go into overdrive.
Problem is, the cells, which are produced
in your bone marrow, aren’t quite cooked
before they’re released.
Because they’re underdeveloped, they don’t
know what to do and just sit there in the
bone marrow, clogging everything up.
People with lymphoblastic leukemia experience
things like super low red blood cell counts
because there’s no room for them to be produced
in the bone marrow.
They also have low immunity to pretty much
everything.
In adults, this type of cancer is rare compared
to other cancers.
But it’s the most common cancer in children,
with about 3,000 new cases in the US every
year.
Gene therapy is a totally new way to fight
it.
The treatment, called CAR-T therapy, takes
a form of white blood cell called T-cells
from the patient.
They’re then sent straight to a lab, where
they’re reprogrammed to attack the cancerous
cells clogging up the immune system.
T-cells are really good at spotting things
that shouldn’t be in our bodies.
They do that by scanning for proteins on the
surfaces of things like viruses and bacteria
using receptors that are kind of like a memory
bank for antigens — anything your immune
system recognizes as a threat.
If there’s a match of antigen to receptor,
the T-cell attacks.
CAR-T is named for an antigen receptor that
researchers add to T-cells to trick the patient’s
immune system into attacking.
Essentially, the T-cell memory bank doesn’t
have a copy of the file, so we’re uploading
it into the system.
And it works really well.
In clinical trials, there was an 83% survival
rate in patients who’d stopped responding
to other treatments.
It’s taken researchers a long time to get
to this point because it’s hard to reprogram
cells, and it’s even harder to do it in
a way that’s both effective and safe for
the patient.
There are only a few other kinds of gene therapy
that have been approved anywhere in the world.
But there are a lot of treatments in the works,
and this first FDA approval could be a catalyst
for more.
In fact, the board is currently reviewing
gene therapy treatments for a similar type
of adult cancer, as well as inherited blindness.
Eventually, we could see gene therapy treatments
for all kinds of different cancers, along
with plenty of other diseases.
This is just the first step.
Also in the war against cancer this week:
Remember the Zika virus that almost canceled
the Olympics last year?
Well, in a paper published on Tuesday in The
Journal of Experimental Medicine, scientists
may have figured out a way to use it for good
— by treating brain cancer.
This isn’t the first time we’ve thought
of using a virus to attack cancer.
Doctors have been using a type of herpes virus
to treat skin cancer for a couple of years
now, and researchers are studying other potential
treatments.
Mostly, these viruses are engineered or changed
in some way.
But it’s possible that we won’t need to
do much to Zika at all.
Zika is a mosquito-borne virus that’s mostly
dangerous because it attacks a developing
fetus’s brain — specifically, a type of
stem cell called neuroprogenitor cells.
These cells are responsible for growing a
baby’s brain, so attacking them can cause
microcephaly, where the brain doesn’t develop
properly, and the baby is born with an abnormally
small head.
The thing is, neuroprogenitor cells are really
similar to a brain cancer cell called a glioblastoma
stem cell.
Glioblastoma is the most common form of brain
cancer.
It leads to a tumor that can only be treated
through surgery and chemotherapy, which often
doesn’t even work.
That’s because of what’s left behind after
the treatment.
As hard as we try, it’s really tricky to
get rid of the glioblastoma stem cells — the
cells that tell the cancer to grow in the
first place.
After about 6 months, the tumor generally
comes right back.
But if we could get rid of these stem cells,
the cancer would be gone for good.
That’s where Zika comes in.
When the researchers tested Zika on glioblastoma
stem cells from human donors, the virus targeted
and killed the cancerous cells while leaving
the healthy cells alone.
And mice with brain tumors infected with Zika
showed a significant reduction in tumor size
after just two weeks.
Injecting a dangerous virus into patients
who are already very sick might sound like
a kind of stupid idea.
But a Zika infection isn’t a big deal for
adults, as long as they’re not pregnant
or planning to have a baby anytime soon.
Our brains aren’t growing, so we don’t
produce neuroprogenitor cells, which means
there isn’t much for the virus to attack.
It just causes a minor fever, a rash, and
maybe a headache.
Most people have no idea they’re sick at
all.
And just in case, the researchers are working
on ways to make the virus used for the treatment
even weaker.
There’s still a long way to go before doctors
start deliberately infecting people with Zika.
But someday, the same virus that caused an
epidemic could save a lot of lives.
Thanks for watching this episode of SciShow
News.
If you’re interested in learning more about
the science of cancer, you can check out our
video about why we haven’t cured it yet.
