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.