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Finding safe, effective cancer treatments is tough, but in the last couple of weeks, we've taken two major steps toward a future where every type of cancer has a cure.

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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 towards 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 in to ways to use it to target the genes and proteins involved in different types of cancers.

Now we are 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. The problem is, the cells, which are produced in your bone marrow, aren't quite cooked before they are released. Because they are underdeveloped, they don't know what to do and just kind of 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 3000 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 cells called T-cells from the patient. They are 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 are 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 has taken researchers a long time to get to this point because it's hard to reprogram cells, and it's even harder to do that it in a way that's both effective and safe for the patient. 

There are only a few other kind 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 cancelled 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 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' brain. Specifically, a type of stem cell called neuroprogenitor cells.  

These cells are responsible for growing a baby's brain, so attacking them cause 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 those stem cells the cancer would be gone for good, and 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 kind of a stupid idea, but a Zika infection isn't a big deal for adults as long as they are 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 are sick at all and just in case, the researchers are working on ways that 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.

 Outro (4:48)

Thanks for watching this episode of SciShow News. 

If you are interested in learning more about the science of cancer, you can check out our video about why we haven't cured it yet.