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Cancerous colon tissue
Dr. Andy Connolly of Stanford Medical School shows us what cancerous colon tissue looks like. Created by Sal Khan.
Want to join the conversation?
- How would you get it?(6 votes)
- Like all cancers, it can be gotten from poor diet, lack of fiber (food sits there), genetic loading ("it runs in the family") and environment, such as poor quality water. There are some other reasons I have not mentioned, I am sure.(10 votes)
- Is there any risk of causing metastasis with surgery?(1 vote)
- Hi David, there are 2 specific risks that require surgical excision of cancerous tissue to be precise and well supplemented with chemotherapy afterwards.
Firstly, whilst it is easier (with practice) to identify dysplastic cells under a LM (as seen above), it is much more difficult when in the operating theatre. There are lots of interesting techniques that go into tracking down how far it has spread but the guiding principle is to take a little bit more than absolutely required, to ensure you get all of it so it doesnt have a chance to resestablish.
Secondly, there is a phenomenon where a primary cancer (the original dysplastic location), and indeed the early metastatic locations, can inhibit the growth of further metastases. It really is unknown how this occurs, but it can mean that there are more, effectively invisible, metastases in the body. Once you remove the primary, then this inhibition is released allowing these further metastases to grow. This is often why people get 'relapses' of their cancer and why 5 year survival rates are still so uncertain. To try and minimise the risk of this occuring, aggressive chemotherapy is often used as an adjunct to surgery, to give the body the best chance of stopping further cancerous growth.
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source: 2nd year medical student at cambridge. large amounts of information being taught on cancer development and pharmacological intervention. Got exams coming up, so if you do see something wrong, call me on it!(8 votes)
- why do slides of cells look pink?(1 vote)
- Cells are transparent, so, in order to be able to study them using, for example, a microscope, they have to be stained. One of the most common stains is hematoxylin and eosin stain. Hematoxylin stains the nucleus blue while eosin stains the cytoplasm pink.(5 votes)
- So cancer is a disease, and not a disorder, or both?(2 votes)
- You are correct in saying that cancer is both a disease and a disorder. It begins merely as a disorder of the cells, but can then spread, and, if malignant, becomes a disease.(3 votes)
- why generally cancer occurs?can it come from parents or ancestors
?(2 votes) - They mentioned pretty in the beginning the role of viruses messing with DNA and also the importance, - logically - of the immune system.
So what exactly is the interplay between the seriousness of inflammation due to infection and the differentiating 'power' or lack thereof, from the blood cells from the immune response. For example leukocytes?(2 votes) - Can change in bowel habits, such as diarrhea, red blood, weight loss be signs of colon cancer?(1 vote)
- Yes, go see a doctor immediately...............especially the blood and weight loss. Don't debate this with yourself. Make the call tomorrow. If you are too scared, have a friend make the appointment for you. Your symptoms are very serious. Don't screw around right now..........you need to find out why it is you are experiencing these critical symptoms. Your body is trying to tell you something drastically. It may be nothing, but don't wait to find out.(3 votes)
- So, this is cancerous because the cells have proliferated and invaded past the boundary drawn in the previous video?(1 vote)
- it is not cancerous purely because they have proliferated (proliferation can be a normal response to an irritant of some kind). It is because they have proliferated in a completely disordered manner, and they have invaded into an area into which they do not belong (past the boundary line). The architecture of the cancerous region does not resemble its surrounding healthy tissue, and the cells do not function or perform their 'jobs' like cells in that region should do (ie they are not producing t(2 votes)
- Also, can't brain cancer come from too much tv?(1 vote)
- More likely that the lack of exercise and poor nutrition often co-located with 'too much TV' would contribute to the conditions most likely to facilitate the development of cancers. Khan videos contribute to enhanced brain function so don't worry too much ;)(2 votes)
- So when it metastasizes, the cancerous cell leaves to go to other parts of the body where it continues to grow. It can survive in other parts of the body? They're still colon cells but they are growing in other places? They do not interact with other cells, right? They just continue to grow and are all descendants of the cancerous colon cells?(1 vote)
- These cells can no longer be called as colon cells, they are cancerous(abnormal) cells. They spread through the circulation / lymphatic system and get ' implanted ' in various tissues. The most common metastatic locations depend on the normal route the blood / lymph takes from the affected organ. Anyway, the cancer cells have mutations that allow them to ignore the normal signals that regulate division and function. Hence they usually outgrow the normal cells and sort of "croud them out". Thus the secondarily affected organ can no longer perform its function effectively and usually it is bigger than normal. It is possible to find out the origin because these secondary metastases produce " cellular markers " similar to the primary carcinoma. Basically proteins expressed on the surface of these cells
On a side note, Cancers and their metastases instead of losing function, can also acquire certain abnormal or perverted functions. Some of them can produce normally produced hormones in excess eg: Chriocarcinoma of the ovary produces a ton of HCG. Other can produce totally unrelated hormones, proteins and enzymes. These are called as " serum biomarkers ". Colon cancer produces CEA ( Carcino Embryonic Antigen ) which is normally found only in the fetus. Levels of these can be measured in the blood. It is primarily used for follow-up and to give a prognosis.(2 votes)
Video transcript
SAL: This is Sal again, and
this part four on the series that we're doing at
Stanford Medical School, with Doctor Connolly. DR. CONNOLLY: All right
Sal, we're back here again. This is now the
fourth of the slides. And this would be
now the business for why that segment
of colon was removed. This is the colon cancer. SAL: Wow, wow. DR. CONNOLLY: And
so just to orient, we'll go now to the drawing. Which is, like you were
saying before, up here this is the lumen. SAL: Right. DR. CONNOLLY: Up here. Out here, that's the-- SAL: Lumen is the
inside of the colon. DR. CONNOLLY: The inside. That's the inside. Out here, this is the
rest of your belly. SAL: Right. DR. CONNOLLY: Where
the bowel is all kind of rotating around
in the abdomen. And so-- SAL: Is there a word for
like intra-abdominal-- DR. CONNOLLY: Yeah, peritoneal. SAL: Peritoneal, OK. DR. CONNOLLY: The
peritoneal cavity is where all the bowel loops are
kind of just moseying around. And then what we
have here is, this is an important
part, which is this is the muscle that
allows peristalsis. SAL: Yes, that's the peri-- I
learned that in high school. That's the kind of moving,
the undulating motion to the push stuff. DR. CONNOLLY: Yep. It'll go and it'll
sort of milk it along in order for the
contents to move along. So you can see, the muscle
looks all fine there. That's how thick
it's supposed to be. And it all looks fine over here. SAL: Just on a scale,
what scale is this? Like how thick is that muscle? DR. CONNOLLY: So
we're now, once again, our tiny little red blood cells
are those little dots there. SAL: Right. DR. CONNOLLY: So we're
talking about the thickness here as a few millimeters. SAL: That muscle is
about a few millimeters. DR. CONNOLLY: Remember
back to this guy, that was about six millimeters. So that's about six-- SAL: OK, OK. DR. CONNOLLY: Millimeters thick. That's actually strong. That's a very,
very strong muscle. And you can kind of
see it goes up here, it kind of comes
around here, but it's looking like it's troubled
all along this area. SAL: Yes. And this stuff, all this stuff,
this once was probably a polyp, and now it's turned into a
kind of this massive polyp? DR. CONNOLLY: Yeah, so we
have the normal over here, for the lining. This is where it's
going dysplastic. It's looking a
little bit bad there. There's where it's
going dysplastic. And so now what
happens is, you've got these edges of dysplasia-- SAL: When people in the
medical field say plastic, they're saying, that
word means tissue? DR. CONNOLLY: Well plastic in
general, like plastic surgery, or the plastics as far
as a material science, means moldable. SAL: I see. DR. CONNOLLY: But it also
means you can grow with it, and it can change shape. SAL: Right. So when you call something
plastic it's moldable tissue. DR. CONNOLLY: It's
the shape change. SAL: It's a shape change. I see. DR. CONNOLLY: And so the
shape changes were wrong. SAL: I see. DR. CONNOLLY: And
actually dysplasia can refer to a cell, a tissue,
an organ, or an entire limb. SAL: Oh, OK. DR. CONNOLLY: So it just
means it grew wrong. Or molded wrong. So now this is where we
have the cell dysplasia. This is all the bad stuff. And it basically started
probably somewhere up there, and is invading in all
of these directions. SAL: This one cell
up there just started dividing uncontrollably-- DR. CONNOLLY: That's right. SAL: And it's descendants. DR. CONNOLLY: It could
have started from one cell being very bad. It often though starts--
and I'm going to change now, so we'll lose our art, and
so what I'm going to do is change this-- that
it often starts, though, from one of these. Meaning maybe a cell went
bad right around there. And now really is
starting to grow. SAL: And when you say grow,
it's not just one cell, it's all of its descendants. DR. CONNOLLY: It's descendants. And billions of
cells are growing. Billions and billions
are growing downward in order to now, in this case,
grow all the way through. SAL: Wow. DR. CONNOLLY: And so you can see
the scale is, it not only grew a little bit, it went
right through the muscle. So going back to this
guy here, this is now-- SAL: And there
are some, the body does have things to fight this
off, but it was unsuccessful. DR. CONNOLLY: Oh that's right. And so there are
certain conditions where if you decrease the immune
functions, you'll get cancer. And so it's still argued
though whether it's that your immune system is
decreased, you got a virus, and then the virus
caused the cancer. Or whether there's a
lot of surveillance there to eliminate cancer. SAL: And the whole notion that
viruses-- it's fascinating. It's because viruses
are messing with our-- isn't a significant chunk of our
own DNA from ancient viruses? DR. CONNOLLY: Yep. And I think there's a couple
big categories is that viruses can get into your DNA and
really screw up the DNA. Like getting integrated into it. But they also, like we said
before, can lead to irritation. And then more cell growth
and have trouble there. SAL: Makes sense, makes sense. DR. CONNOLLY: So
now we're back here, in which we're
looking at the cancer. Which probably, like
you said, started here. And is growing,
including spreading out all the normal tissue around it. SAL: Wow. DR. CONNOLLY: And so we're
going to look now at the cells. So zoom in. Zoom time. Hang on to your hat. OK, so what we're going
to do is first-- probably go into a lower power here--
is look at the edges of this. So once again, we find normal. And so this is even
not perfectly normal, you can see it's a
little bit dividing and a little bit irritated. So this is irritated
along the edge. SAL: Hyperplasia. DR. CONNOLLY: Exactly. SAL: I'm like, I'm
learning something. DR. CONNOLLY: All right. So then what we have now
is, as you go in deeper, these are the areas
which are normal, but this is all
kind of coming out. Like we were saying
up here, kind of growing out in
all directions. This is now where you can see
the cancer, next to the normal. You know we had talked
before about dysplasia. This is really bad. SAL: With a capital B. DR. CONNOLLY: Yep. Small children off
the street could be able to tell you
that this is bad. SAL: Right. After they watch this video. DR. CONNOLLY: Exactly. And so these are
the normal ones. They're doing their J-O-B job. Making the mucin,
nuclei at the bottom. What is this guy doing? It's just chaos. So before we talk
about carcinoma in situ, a cancer in spot. If you saw cells this bad, you'd
say do not let them go far. Because they will have
a tendency to invade. They're crazy. So this right here's a
bunch of the cells, that's a bunch of the cells,
they're these guys here. You can see they're really
haphazard, they're growing, they're not doing their-- SAL: So if we found a polyp
that had this stuff that didn't cross that boundary line
yet, we still would say no, we've got to take this-- Well
I guess we already took it out. DR. CONNOLLY: We took it out. So cancer of the colon
is one of the ones where surgical cure is
still a classic. Cut it out, and you're
probably in pretty good shape. And so there you'd
say, well if it's the tip of the polyp
that looked like this, I think we got it out. But you'd say to yourself,
we better watch this person. SAL: I see. So if the whole polyp
kind of looked like that, you're like, oh let's
cut out a bigger section. DR. CONNOLLY: Yeah
then you might. So if it's going
down into the neck, or getting a little
further, or if you've cut across it at the
margin, then watch out. But here's the problem. Is remember how I said up
here it's not a big deal, but once you get down near
the veins and arteries? These guys are running amok
down by the veins, the arteries. SAL: And so you can actually
see these cells have split off. And they're infiltrating. Wow. DR. CONNOLLY: So you
can see these guys here. So that's one little
nest of cells. There's one. That's probably, right
there, a cancer cell just dying to get
into that little vein. SAL: So this is actually, I
can never say the word, meta-- DR. CONNOLLY: Metastasis. SAL: This is it. We're seeing it. DR. CONNOLLY: This is
where it would come from. SAL: This is where it's
starting to happen. DR. CONNOLLY: So these
guys are the bad actors. They're growing in next to
these very fragile little blood vessels, and so that guy
is knocking on the door. Once he gets in here, that's a
venule, meaning a little vein. That's the road out. SAL: Right. And it just looks like a
circle here because it's a two-dimensional
cross-section of it, but you can imagine it popping
in and out of our screen. DR. CONNOLLY: Yes. It would be popping in
and out of our screen. So this guy would kind of
go in and out of the screen, connect to this one, and
then it would go out. SAL: And it's
officially-- I can never say the word--
metastasized once it's found a beachhead
someplace else? DR. CONNOLLY: That's right. So it's considered
a metastasis where, let's say, the cell got into the
vessel, if it left the region. So it went to the
lung, the liver. This is looking
like you really are worried that this
could metastasize. SAL: Right. DR. CONNOLLY: And so
what's interesting about this is that when you
look at something like this, there's such a thing
called, for cancer, grade. And what grade is,
is basically what we we've been just talking
about, how bad does that look? SAL: Right. DR. CONNOLLY: And so the grade
is, wow, that looks nasty. I think that-- SAL: Is nasty a technical term? DR. CONNOLLY: Actually
we use it quite a bit. Some people say, oh what
did that tumor show? We say it was nasty. When we talk about nastiness,
it's a lack of behavior. If you can get a cell where
the nucleus gets that big, or sometimes it's that
big, there's chaos. And there's chaos not
just in nuclear size, but how it behaves. SAL: And I guess
the nuclear size is a telltale, because that
means that the cell is devoting a lot of its resources
for replication and-- DR. CONNOLLY: It's
for replication, but it also means, to me, that
normally things in the cellar are very orderly. You do not divide your DNA
until these things are already [INAUDIBLE]. And now it's just
left and right. So yeah, this would
be a high grade tumor. And then stage is
the other main thing. SAL: Yes, I've heard of stage. DR. CONNOLLY: Stage means,
where is it in the body? So in this case, if it's these
nasty cells at the very top, it's actually a lower stage
then if they're nasty cells and they've come all
the way down here. SAL: So in situ carcinoma
would still get a stage. DR. CONNOLLY: It's a stage 0. SAL: Stage 0. DR. CONNOLLY: So it's
basically you're nowhere. And then if you begin to
just cross over, like here, and invade, then
you're in stage 1. And then there are depths
as you go for stages. And then there's
always the other thing, where did it go off to
other parts of your body. And that's the
very highest stage. SAL: And so this
isn't a-- and this is true of all cancers, when
people about breast cancer, I've heard it in
that context a lot. Stage 1, or stage 0 through 4. So it isn't just the size. If the cancerous tissue is big,
but if it's in a safe place, it could still be
stage 1 or stage 0. DR. CONNOLLY: It is. What's interesting about staging
is almost the whole world has agreed to do the
same kind of staging. And that staging is
what we're calling TNM. And T has to do with how
big it is, and the one site, and how much it's
crossed any barriers. SAL: Right. But the barrier crossing sounds
like the most important thing. DR. CONNOLLY: It does. Although this one here is,
are they in lymph nodes? SAL: Oh, right. DR. CONNOLLY: And
the lymph nodes are nearby structures
where the lymph goes. And so that's one road out. And the other one is metastases. And so yeah, the staging
has to do with all three. SAL: I see. And metastases always
happens through the circulatory system--
Through the blood, the vessels? Or does it also happen
through the lymph network? DR. CONNOLLY: And
so it's something where going through the lymph
nodes, for something like this, is one of the first steps. But getting to the
liver and the lung, it's got to get into the
blood vessels somehow. The lymphatic in your colon
connects to a local lymph node, but does not connect through
lymph only to the lung. SAL: I see. DR. CONNOLLY: So it must have
gone into the blood somewhere. So that's the way it looks here. And then the final thing here,
when looking at this cancer, is if we go over here, this is
the greatest depth of invasion. You had asked me about the
body's immune function. Well if you look here, now
you see how it's kind of loose and there are all these
little immune cells? That's what these guys are. Those are-- SAL: What's the immune cell? DR. CONNOLLY: These guys here. See the little round guys? Those are lymphocytes. SAL: I see. I should circle it, actually. How can you tell the difference
between the lymphocytes and the cancer cells? DR. CONNOLLY: That's
because I'm a pathologist. SAL: That's because you've
had many years of training. DR. CONNOLLY: No, but they're
the little round ones. So this one right here
is a classic cell, which is called a plasma
cell, in which there's a nucleus here, and all the rest
of this is making antibodies. SAL: You're not
circling that area? DR. CONNOLLY: No,
I'm just drawing. SAL: Oh, OK. You're just drawing. DR. CONNOLLY: So
this guy is this one. I drew him right-- SAL: OK, you're
zooming in on this. DR. CONNOLLY: Yeah,
zooming in on that. So yeah, that's a plasma
cell, meaning it's a nucleus-- SAL: I just want to clarify,
what you've circled there, just because it could be
a little bit confusing, but we have this big circle
is maybe we [INAUDIBLE]. DR. CONNOLLY: This is why I
should leave it to the pros. SAL: No, just because
I'm getting confused. You're not circling that area. DR. CONNOLLY: No, no,
I'm not doing that. SAL: You were just showing
what it looks like zoomed in. DR. CONNOLLY: Right, so
that's a plasma cell. SAL: That's a plasma cell. DR. CONNOLLY: That's
making antibodies, probably against the tumor. And so that's the immune
response in that spot. SAL: And how do you know
that's-- That looked very similar to the
cancerous cells to me. DR. CONNOLLY: This one's
a little hard to tell. And if you had a real microscope
you'd turn up the light. And we'd have a very
specific look to the nucleus. And then these guys over here
have little pink granules in them, which is a
type of immune cell. And so when looking
through here-- SAL: On this depth, which
ones are cancerous here? DR. CONNOLLY: OK, so now
let me just get over here, to this one here, and then
come out just a little bit. Let me go over here. Is that when looking
at these guys, these are all inflammation. The nearest cancer cell
where I could bet the farm are these guys up here. SAL: Oh, OK. See, when you see on this
view it becomes more obvious. They definitely look different. DR. CONNOLLY: They
look different. And so then when you come
out here, you can see, there's the cancer. This is the body's reaction
to the cancer right there. SAL: I see. DR. CONNOLLY: At
the deepest zone. And there are therapies
based on trying to get more of this
immune response. SAL: That's amazing. Very cool.