What is Cancer?
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What is Cancer?

Hi. It’s Mr. Andersen. Over a million people
every year develop cancer. There are over a hundred different types of cancer. But many
people don’t really know what is cancer? And the answer to that question is very simple.
If we look at a normal cell, on the inside of the cell is the nuclei. And that contains
DNA. And the DNA contains genes that control the actions of the cell. And one of those
important actions is how a cell makes a copy of itself. How it goes through what we call
the cell cycle. And so if you take a normal cell and put it in culture it will simply
make a copy of itself. And if there’s room those cells will make copies of themselves
and they’ll keep doing that until they fill up that area. And if one of these cells dies
then an adjacent cell is going to jump into that cell cycle and it’s going to fill that
hole. And so that’s how you went from a zygote to the trillions of cells that are inside
your body. And that’s also how you replace cells. And so your skin is constantly losing
cells off the surface. But we’re creating cells underneath that. And so the cause of
all cancers is the same. There is going to be damage to the DNA. And so that DNA is made
up of what are called nucleotides. And there are tons of genes in there that are controlling
this cell cycle. When a cell should make a copy of itself and when it should stop dividing.
And so a mutation is simply damage to that DNA. Now it could just occur spontaneously.
If we all live long enough we’re all going to develop cancer because these mutations
are going to start to accrue during our life time. But we can also increase the rate of
those mutations using the environment. And so for example if we smoke cigarettes that
could cause mutations to the DNA. Increases in UV radiation. We’re finding decreases in
exercise. Increases in certain types of diet can cause mutations. And that can cause problems
in the cell cycle. And so let’s say we get a mutation in this cell right here. There
are going to be genes within that cell that sense something is wrong. And lots of times
it will undergo apoptosis where that cell dies and another cell moves inside. But during
our lifetime we start to accrue more and more mutations. And eventually enough mutations
build in one of those cells and it becomes not a normal cell but a cancerous cell. And
this takes a long time for that to occur. And so this is a pretty awful graph. This
is the increase in the popularity of cigarettes. And so this is the number of cigarette smoking
per person per year. And so as they were doing that they were increasing the mutations inside
their body. And we can look decades later, we see the causation. We can see an increase
in lung cancer in men as well. And so as we make those mistakes in our cell we form these
cancerous cells. Now what does a cancerous cell do? It doesn’t matter that there are
cells around it. It is simply going to divide and divide and divide. Over and over and over
again. And eventually what you create is a tumor. Now there are two types of tumor. If
those cells are restricted to that one area and stay within a membrane we call those benign
tumors. And that’s not cancer. But if there is no restriction to that area it becomes
what’s called a malignant tumor. And that’s really a definition of what cancer is. It’s
when we have these uncontrolled cell growth and those cells show uncontrolled cell growth
spread throughout our body. And so this is a video of some cancerous cells. And so instead
of just growing and doing the jobs of the cell, you can see they are kind of misshapen.
And all they do is make copies of themselves and copies of themselves over and over and
over again. That’s where all of the energy is going. Now if that was restricted to one
area it wouldn’t be as big a deal. But they can move to different areas of the body. And
so if we have a tumor right here, it can start to invade the tissues around it. And so that
tumor can not only get larger, but it can move into new areas. And if that tumor gets
into the lymphatic system or the circulatory system, it can move around our body and it
can settle somewhere else. And so that’s the problem with a malignant tumor. And so we
name cancers based on the tissues and the organs that they infect. So this would be
lung cancer. But we could also have colon cancer. Or maybe pancreatic cancer or breast
cancer. It’s basically named on the tissue of where it is. Now each of those cancers,
even though the cause is the same, damage to the DNA which produces uncontrolled cell
growth, the way they manifest the disease is going to be totally different. And so if
you look at this x-ray we can see that this is somebody who has lung cancer. And there’s
going to be a tumor right there. And what we’re finding is not only are all these different
types cancer different, but each of those individual tumors are different. And between
two people those tumors are going to be different. And even within the cells of the tumor they’re
going to be different. And so what does that mean? Well even though we might treat one
tumor, we’re going to find that within that tumor there are going to be different cells.
Each of those have different genetic problems. And so we could treat most of the tumor, remove
most of it, but it is going to come back eventually over time. And so what do we have for treatments?
And so since cancer is uncontrolled cell growth we want to find those cells and quickly as
we can. And so screening is the most important thing. Once we find that cancer has developed
and we find that tumor, the first thing that we want to do is we want to remove that. And
so surgery is generally what happens next. We remove that tumor. We also use radiation.
In other words we’re not going to be able to remove all of those cell. There are going
to be extraneous cells around it. And so we can target this with ionizing radiation. And
we can kill all those cells. Now this has dangers as well. And so we try to restrict
that to that one area. But it can cause damage to the cells around it. And then often times
we’ll use chemotherapy. Now what is chemotherapy doing? It’s going throughout your whole body.
And it is targeting cells that are actively dividing. Cells that are going through this
cell cycle. And so that’s why it affects, for example, you get a lot of nausea. Because
it’s affecting those cells in your digestive tract. Or you lose your hair because it is
affecting those cells that are quickly making, that are constantly making new hair. And so
with all of these we’re getting better and better at treating cancer. What’s the future
hold? Well we’re really just treating just all cancers with these three methods the same.
And so what we’ll see is if we can get into the genetics and we start to understand how
each of those cancers are different then we can start to target them. And so one of the
breakthroughs was Gleevec which is one of these first drugs that’s targeting a specific
type of leukemia. And it was affecting a specific machinery within that cell. And so again,
the more we understand about cancer we find that they are all the same but the causes
are going to be different. And so what is cancer? It’s simply uncontrolled cell growth.
And I hope that was helpful.

74 thoughts on “What is Cancer?

  1. Why can't the macrophages and killercells in the immune system kill this tumor? Please like so Bozeman can see this.

  2. But, isn't mutations which causes all cancers? You said that the causes are different, but cancers are the same. I'm a little confused regarding that

  3. you cannot tell me what cancer IS, unless you know the CURE…if we knew what cancer is then more than LIKELY, we would be able to cure IT…!!!!!!

  4. The cells in the tumour are the same, aren't they? Because they are the progeny of one genetic mutational cell.

  5. I know this is the standard explanation for cancer (ie, cell starts going crazy not listening to body and replicating). But from what I was hearing, a cell starts to out-compete other nearby cells at which point the nearby cells will start to ramp up to compete. Until we have a cancerous growth of many different types of cells. If it were just a cell multiplying then wouldnt it be a homogeneous growth? 

  6. Parasites are almost unavoidable and they need to sense their environment too. So what if someone genetically modified a parasite to feel or sense tumors. The parasites could be engineered to kill the cancer cells. This could possibly eventually work.

  7. Well done, this is a good introduction video to tumor forming cancers (About 85% of all cancers) 
    We desperately need better ways to more accurately Grade and Stage cancers (Truly knowing early-on which mutations are really dangerous ones). Without good low-cost methods to measure the metastatic potential of a cancer the quality of expensive cancer studies has always been compromised.

    Perhaps one of Mr Anderson students will be part of the solution one day. You have a really excellent teacher here.

    Other obstacles have to be overcome, 
    Inefficient business models V's Passionate scientists being free to work together
    Gains for Individual companies V’s Patient Impact 
    Publicly Funded Science for Sale (Behind pay walls V’s “True” Open Access 

  8. Though I thought the video was quite informative and overall well presented, your use of the word "tumor" is incorrect.  It is more appropriate to call the collection of cancer cells a mass or nodule. "Tumor" refers to any abnormal swelling (bug bite, swollen stubbed toe, etc.)  and is not remotely synonymous with cancer in a medical/pathological context due to its extremely broad/nonspecific meaning. The more correct way of defining cancer is "malignant neoplasia."  It would serve those interested in understanding the differences of the following terms: hyperplasia, neoplasia, malignant, and benign.

  9. How does uncontrollable cell growth lead to death of a tissue or organ? Is it because all the energy of that part of the body is being spent on the production of cancer cells & therefore not on the healthy cells?

  10. An interesting documentary was Forks Over Knives. Individuals discovered that a diet rich with fresh vegetables, and eating no meat, permit the body to heal from many illness. It's also interesting to see so many individuals Living to Prevent Cancer.

  11. I'm confused as to why Leukemia is considered a cancer. As far as i know it's a malfunction in the production of white blood cells, but i dont see how a malignant tumor would be involved in any way to this, so why is it labelled a cancer?

  12. You said one treatment of cancer is using ionizing radiation, but does ionizing radiation not cause DNA strands to break and thereby damage chromosomes… cause mutations that may trigger a tumour to develop in the first place ?. Seems contradictory, please explain.

  13. Wish you went more into anchorage and density dependent inhibition because that's how it's characterized in AP Biology. But great video they're all so helpful!

  14. All cancer is the same. That part is true, however, the RNA/DNA and the mutations are not important and subsequently the genetic research in these areas will not result in any major breakthroughs because the actual cause is too simple (and free) and is thus ignored. Otto Warburg figured this out in the 1920s and was awarded the 1931 Nobel Prize for his discovery. He was able to turn cancer on and off by regulating the oxygen tension upon the cell and feeding the culture glucose. The cellular respiration becomes impaired from inadequate lymphatic drainage resulting in hypoxia which is technospeak for cellular starvation for oxygen. Warburg observed that the normal fuels that eventually produce ATP, change due to external influences. The fuel source mechanism for cellular energy production, responds to a shift in respiration away from using oxygen and fats towards less oxygen and sugars as a survival mechanism. The reaction of burning sugar (abnormal) for energy resides in a fermentative state and it is the impact of these external influences which trigger the malfunction of the cellular machinery. Researching the internal changes of the genes etc., is pointless because by increasing the lymphatic fluid flow rate to a degree where the waste products of metabolism are adequately removed and the required nutrition is restored, cancer goes away on its own. In  other words, cancer is curable via the diet and improvement in waste removal via alterations in personal hygiene. A tumor is not the cancer but is a containment vessel that the body constructs so as to wall off what amounts to a cesspool of necrotic (dead) tissue. The tumor is identical to a placenta and the tissues are identical. Cancer is a systemic condition and the resultant tumor formation is simply a local manifestation. Cutting out the tumor does not resolve the condition and it is well-known that cancer tumors nearly always come back and do so with a vengeance.

    Modern day research has been a failure and will remain fruitless in the foreseeable future until common sense is restored. This is a simple disorder and it can be cured if one follows the laws of Nature. Carmi Hazen

  15. Man… This is so familiar. Last year my grandfather had prostate cancer so he had to have prostate removal surgery, followed by about a years worth of radiation treatments. Do to the cancer being in his prostate a lot of my friends were giggling about it! Cancer is not funny, and cancer cells is absolute cellular psychopaths…

  16. Wait just a second… correlation shows causation? I think not! C'mon Bozeman. I love your videos but that's a scientific no-no right there. (2:35)

  17. Great presentation! Love how you add the animation to your discussion! Very easy to understand! Keep up the great work!

  18. Liar ! Medical explanations FAILED . You, medical drs are Liars. You fail miserable . Cancer is a cell surviving without Oxygen. For naive people : medical drs has more cancer than general population. They cannot help themself….so…. How is going to help YOU.

  19. A fine explanation of cancer, but it focuses more on therapy than on causes and prevention. In that sense, a corporate-friendly neoclassical explanation..

  20. Yes it was helpful. I was recently informed of a large tumor that must be removed, and I will learn if it is cancerous in a few days. Therefore, this short informative video was a great refresher tool to remind me of the cause of tumors. Thank you!

  21. Actually a study shown if your active through you 60ss and above less likely chance of cancer the more you exersice the more healther all the way around less chance of cancer

  22. Whatever the lump is it's not painful so for all intents and purposes, for me as the individual, it's a non-issue.

  23. Thanks for the vid I never seen cancer and never know what cancer is! Thank you! 😁😁😁 and wow your smart smarter then me

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