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Stop Saying Sharks Will Cure Cancer

Thanks for CuriosityStream for supporting this episode! Go to to learn more { ♪INTRO } It seems like every time scientists learn
something about sharks— like, a new genome is published— everyone suddenly starts going on about whether this new bit of information will finally show us how sharks will cure cancer. And there’s no doubt about it— sharks are awesome. And they can do some pretty incredible things. But wiping human cancers off the face of the Earth is not ever going to be one of them. Sharks are not invincible. They still get old. They get sick. And just like the rest of us, they can get cancer. There’s no magic cure hidden in their genes— just like there wasn’t one in their cartilage. So let us kill this zombie of a myth once and for all. The idea that sharks are swimming cancer cures
all started in the 1970s. Back then, researchers observed that cartilage— a flexible but firm kind of connective tissue— inhibited blood vessels from developing into
different kinds of tissues. Since tumors tend to need a lot of blood to
survive and grow, blocking this kind of blood vessel formation
could help treat cancers. And a shark’s skeleton is primarily made
up of cartilage. Lo and behold, when researchers stuck shark
cartilage near tumors, it turned out it, too, restricts blood vessels
from developing into them. Lo and behold, when researchers stuck shark
cartilage near tumors, it restricted the growth of new blood vessels. Somehow, that led people to think that sharks
never get cancer and ingesting shark cartilage in pill form
could be used to treat cancer in humans. This turned out to be flat-out wrong— multiple studies have proved that shark cartilage is not an effective treatment for cancer. And sharks definitely get cancer. Scientists have even found ones with tumors
in their cartilage. So countless sharks around the world were
slaughtered for nothing, and to make matters worse, this myth pulled
desperate cancer patients away from actually helpful treatments. Now, the myth is back once again, but this
time, the secret cancer cure is supposedly hidden
in their genes. This all came up in 2019 because scientists
were finally able to figure out what the genome great white sharks looks like— and they found some interesting things. Like, the animals have unique adaptations
in genes associated with fighting infections and aspects
of wound healing like blood clotting, which could explain how
they mend their tissues so quickly. And their whole genome is one-and-a-half times
larger than the human genome! A lot of that extra bulk is thanks to genetic
features called LINEs. These small DNA segments are a kind of transposon, meaning they can move around on their own. And the proportion of LINEs in the white shark
genome is among the highest found in vertebrates
so far. That’s of note because LINEs can cause genomes
to become unstable, resulting in cancer. You see, a cell only becomes cancerous after
enough errors have accumulated in its DNA—errors that make it grow and
divide when it shouldn’t, for example. So with all those jumping genes, you’d think
white sharks were super prone to developing cancer. But they’re probably not, and that’s likely
thanks to remarkable DNA repair. The researchers working on the white shark
genome discovered the animals also have a lot of
tweaks to genes that help fix DNA damage. That suggests the sharks have evolved a very
effective genome clean-up crew— though functional studies would have to be
done to confirm that’s true. Their repair mechanisms might even be good
enough to make their risk of getting cancer lower
than other animals’. But… that doesn’t mean they can’t get
cancer. Scientists don’t actually have any evidence
that sharks develop tumors less often than other vertebrates. And they have caught wild great whites with
cancerous tumors. But let’s say for a moment these DNA repair
mechanisms are so amazing that the animals get cancer less often than,
say, humans. That still doesn’t really help us treat
humans with cancer. DNA repair mechanisms aren’t things we can
inject or swallow to improve our cells’ ability to fix genetic mistakes. If we wanted to take advantage of them, we’d have to do something drastic like add
them to our DNA. And I think we’ve all learned from King
Shark’s supervillainous ways that engineering human-shark hybrids is bad
idea. Also, that would only maybe prevent cancer. Great DNA repair can help keep a cell from
developing cancer-causing mutations. But once a cell is past that tipping point,
it’s not able to undo them. In fact, making DNA repair better once you
have a tumor actually makes matters worse. That’s because health professionals often
use treatments like radiation therapy to damage the genetic material
of cancerous cells, effectively killing them, and stopping their
growth. But if repair mechanisms in those cancerous
cells work too well, they might fix the damage, allowing the tumor
to bounce back. So oncologists are actively looking for ways
to block DNA repair. There are molecules, called DNA repair inhibitors,
that gum up these processes. And in theory, if you treat a patient with
one of those, then traditional measures like chemotherapy
or radiation therapy will inflict enough damage to kill the cancerous
cells. The hard part is finding something that can
slow or stop DNA repair in tumor cells without causing too much harm
to healthy cells, because, you know, you don’t want to make
more cancers while you’re treating one. Still, there are some potential candidates
already being tested. For example, a compound called mibefradil
dihydrochloride can hamper DNA repair in brain tumor cells, and clinical trials of the stuff to date have
been promising. So in short: sharks are awe-inspiring creatures. They’re amazing and we should learn as much
as we can about them. But the cure to cancer is not locked away
in their cartilage or their DNA, since their effective repair mechanisms can’t
reverse cancerous mutations. We maybe, maybe could learn a bit more about
DNA repair by studying their unique mechanisms for it, and that, in a very tangential way, could
eventually lead to new drugs that help shut it down when we need to. But that even is kind of a stretch. And all this focus on how they’re going
to cure cancer distracts from the important stuff we can
learn by studying them. Digging deeper into those novel infection-fighting
mutations could lead to new kinds of antibiotics that
help us stay one step ahead of resistant microbes, for example. Or, understanding how sharks repair their
flesh so quickly could lead to topical treatments that help
seal up surgical wounds faster or reduce scarring. And ultimately, most of what we learn from
sequencing shark genomes isn’t directly related to human health. Comparing their genes to ours and other animals can provide new insights into how these animals
evolved and how evolution works in general. So sharks can help us answer bigger questions
about life on this planet and how we all got here. And that makes them worth studying, even though
they probably aren’t going to cure cancer. There’s just so much we that other living
things on this planet can teach us. And if you like learning about those things, you might like the videos you can watch through
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the sign-up process. { ♪OUTRO }

  • Go to to start streaming Catalyst Season 1. Use the promo code ‘scishow’ during the sign-up process to get your first 30 days free.

  • When you start studying genetics and realise that about 44% of our genome consists of transposable elements, some of which might become spontaneously active and move into one of our genes. Oh and soft shell clams can get leukemia!

  • So just possible cancer resistance and super healing, with some fancy jurassic park type gene splicing atleast.

  • 1:36
    | "Multiple studies have proved that shark cartilage is not an effective treatment for cancer"
    | "have proved"

    Verb regularization in action.

  • Years ago I falsely assumed a documentary about sharks was correct when it stated they don't get tumors, it didn't take too long to learn that they do. How anyone assumes that an orally administered pill of shark cartilage can cure cancer is beyond me. I dream of a day where everyone has enough basic knowledge to realize that that has to be a scam.

  • Arnold's Sharksnegger: I have a headache

    Juvenile shark: maybe you have a Tuna

    Sharksnegger: Is not a tuna!

  • When I did a research paper on sharks, I found there’s a specific kind (I don’t remember which) that has a compound safe for humans that can also be used to track the development of some diseases, idk if that would include cancer tho

  • Hmmm, shooting up shark cartilage for cancer? Reminds me of whacky black death 'cures' like rubbing half a chicken on the boils.

  • Shark cartilage, the new rhino horn or snake oil. One wonders what would happen if we really figured out a way to lengthen telomeres stop mutations in healthy cells & terminate all malignant cells. How long would we live? Would we have problems with memory & time? Would older generations hold back new generations because they're sticking to old norms just like during the civil rights movement? Would war become more accepted or more abhorrent with death becoming more of a distant instead of short term certainty?

  • i feel like this is purely a result of a misunderstanding of what cancer is*. i've always felt like cancer would be better described as a *condition instead of a disease, as I think that the term 'disease' implies certain things about how cancer develops that are untrue when compared to, say, the measles.

    1 – 🦈 do NOT cure cancer (which they DO get)
    2 – Vaccines💉 are SAFE, and people refusing to use them is why "simple" diseases are now at epidemic levels
    3 – Climate Change🌍🌡 is real, is the fault of humans, and has to be defeated within the decade
    4 – Sex Education leads to SIGNIFICANTLY FEWER unwanted pregnancies🚼 and STDs/STIs
    5 – Apollo astronauts DID walk on the 🌒
    6 – Racism, sexism, homophobia, classism, and religious bigotry ARE ALL REAL
    7 – Universal Healthcare💊 is a right

  • I know this for a fact because when my high school science dissected sharks we found tumors literally everywhere, and the were baby sharks.

  • Can I just say that this was the first time I have ever heard of someone thinking that sharks could hold a cure to cancer? Did something happen to make this video necessary if it was such an old rumor?

  • Stop saying cancer like it's one disease. There are myriad types of cancer. At least one for every type of tissue and cell in the body, sometimes more than one. Each of those different types of cancers have different causes and There will never be a single cure for cancer because each cancer has different prognoses. They also have different treatments. I worked in oncology as an RN and am now retired. While my heart goes out to those with cancer the treatment is getting better.

  • Many cancer cures already exist. From the works of Dr. Weston A Price, Dr. Waglburg, Dr. Max Gerson, Orthomolecular therapy, gerson therapy, the list is endless on the kind of modalities capable of curing cancer. Enough with the bs. This is no conspiracy, this is science. Some of the docs I mentioned were Nobel prize winners in their field.

  • Sharks most definitely could wipe out Human cancer from the face of the earth.
    They just have to eat all humans, no humans, no Human cancer.:p

  • All I want from sharks is the ability to grow more sets of teeth, even after my adult teeth have grown in. I want to able to grow shark teeth in my human mouth. I want to be able to grow and regrow teeth continuously, like sharks do. That's all I want from sharks. Just add that to human dna and I will be happy. Ok, understood?

    [Yes, I do brush my teeth twice a day ever day and take good care of my teeth, but it doesn't help. Bad teeth runs in my family and I feel like shark teeth would fix that. Where's a mad scientist when I want one?] lol

  • That moment when the question is in the thumbnail and the answer in the title. So you don’t actually have to watch the video.

  • I'd already clicked "like" before you even got to the joke about "King Shark's villainous ways"… I guess I'd better subscribe and comment, too.

  • Squalamine is a steroid like compound isolated from the liver of Squalus sharks. It has shown to have anti-microbial and anti-angiogenesis properties, thereby contributing to prevention of tumors by stopping new blood vessels to form to nourish them. Little progress has been made in clinical trials, but the idea that shark medications are a myth or that we’ve only ever observed potential DNA repair genes is false. This could very well be a promising treatment in the future, and much research is in development. (Note, it is now made synthetically instead of isolated for shark liver, so the study of this molecule causes less of a threat to natural shark wildlife.)

  • Why do people target such majestic creatures as sharks for their fake medicinal cures? Why not target those jellyfish that can supposedly grow younger over time? Jellyfish are assholes AND they're overpopulating our waters due to increasing ocean temperatures! It's a win-win (minus the fact that the medicine will still probably not work)!

  • HEY! King shark's isn't a genetically engineered hybrid between a human and a shark, he's just the son of a shark god, totally different.

  • This video is a lie created by liberal media socialists that think the world is round. Sharks are the answer since the aliens won't help

  • If sharks cure cancer trump should have one nailed to every wind turbine that he thinks causes cancer. Problem solved.

  • does anyone else get confused when Hank hosts SciShow because your used to seeing him on CrashCourse?
    Not saying we should get rid of him though, MORE HANK!

  • What! you mean Discovery is wrong! "Sharks Are Helping Find A Cure For Cancer | Shark News"


    Published on Jul 20, 2018


  • What causes cancer in marine animals? is it because of the presence of microplastic plastics in the water?

  • The very liberal use of the word "cure" is just funny and sad all at once.
    Let's be honest, if humans are ever going to have something like a cure fof cancer, humans will have to make it themselves

  • Scientist could use a crisper to add certain parts of sharks DNA that would allow humans to have the sharks DNA repair Factor.

  • Nanobots could cure many different diseases including cancer. This seems more likely in the coming decades to me, than finding individual cures for every single disease and ailment that exists.

  • Could cellular repair mechanisms not be helpful to people predisposed to cancer? Like if someone has one faulty allele of a gene that suppresses cell division so is more likely to get cancer as they only require mutation in one allele for out of control cell division. Surely if we had a treatment like that it would help decrease the chances of the cancer recurring. Even as a preventative measure in older people! It probably wouldn't work but it's be worth looking into surely

  • This bug can fly, thus if I eat it, I can then fly too.
    This horse can shoot fire through his mouth, therefore if I eat them I will be able to do that too.

    The people that says these things could count the number of neurons they have with the fingers of their hands, if they knew how to count.

  • I actually thought the title was clickbait because it sounds so ridiculous. Wow people can get desperate

  • What if we ifused the genome of tardigrades with ourselves…

    Like you would have a self modifying genome if you do

  • Right because according to u only your big pharma overloads can cure cancer. I'm done with this channel. You guys are tools.

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