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.