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  • 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.

Hi. It's Mr. Andersen. Over a million people every year develop cancer. There are over

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