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This is a talk about sugar and cancer.

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I became interested in sugar[br]when I was in college.

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Not this kind of sugar.

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It was the sugar that our biology[br]professors taught us about

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in the context of the coating[br]of your cells.

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Maybe you didn't know that your cells[br]are coated with sugar.

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And I didn't know that, either,

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until I took these courses in college,

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but back then --

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and this was in, let's just[br]call it the 1980s --

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people didn't know much about why[br]our cells are coated with sugar.

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And when I dug through my notes,[br]what I noticed I had written down

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is that the sugar coating on our cells[br]is like the sugar coating

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on a peanut M and M.

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And people thought[br]the sugar coating on our cells

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was like a protective coating

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that somehow made our cells[br]stronger or tougher.

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But we now know, many decades later,

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that it's much more complicated than that,

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and that the sugars on our cells[br]are actually very complex.

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And if you could shrink yourself down[br]to a little miniature airplane

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and fly right along[br]the surface of your cells,

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it might look something like this --

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with geographical features.

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And now, the complex sugars[br]are these trees and bushes --

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weeping willows that are[br]swaying in the wind

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and moving with the waves.

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And when I started thinking about[br]all these complex sugars

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that are like this foliage on our cells,

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it became one of the most interesting[br]problems that I encountered

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as a biologist and also as a chemist.

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And so now we tend[br]to think about the sugars

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that are populating[br]the surface of our cells

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as a language.

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They have a lot of information[br]stored in their complex structures.

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But what are they trying to tell us?

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I can tell you that we do know[br]some information

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that comes from these sugars,

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and it's turned out already[br]to be incredibly important

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in the world of medicine.

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For example, one thing[br]your sugars are telling us

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is your blood type.

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So your blood cells, your red blood[br]cells, are coated with sugars,

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and the chemical structures of those[br]sugars determine your blood type.

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So for example, I know[br]that I am blood type O.

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How many people are also blood type O?

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Put your hands up.

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It's a pretty common one,

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so when so few hands go up,[br]either you're not paying attention

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or you don't know your blood type,[br]and both of those are bad.

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(Laughter)

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But for those of you who share[br]the blood type O with me,

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what this means is that we have[br]this chemical structure

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on the surface of our blood cells:

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three simple sugars linked together[br]to make a more complex sugar.

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And that, by definition, is blood type O.

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Now, how many people are blood type A?

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Right here.

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That means you have[br]an enzyme in your cells

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that adds one more building block,

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that red sugar,

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to build a more complex structure.

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And how many people are blood type B?

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Quite a few.

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You have a slightly different enzyme[br]than the A people,

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so you build a slightly[br]different structure,

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and those of you that are AB

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have the enzyme from your mother,[br]the other enzyme from your father,

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and now you make both of these structures[br]in roughly equal proportions.

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And when this was figured out,

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which is now back in the previous century,

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this enabled one of the most important[br]medical procedures in the world,

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which, of course,[br]is the blood transfusion.

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And by knowing what your blood type is,

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we can make sure,[br]if you ever need a transfusion,

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that your donor has the same blood type,

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so that your body[br]doesn't see foreign sugars,

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which it wouldn't like[br]and would certainly reject.

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What else are the sugars on the surface[br]of your cells trying to tell us?

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Well, those sugars might be telling us[br]that you have cancer.

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So a few decades ago,

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correlations began to emerge[br]from the analysis of tumor tissue.

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And the typical scenario is a patient[br]would have a tumor detected,

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and the tissue would be removed[br]in a biopsy procedure

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and then sent down to a pathology lab

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where that tissue would be analyzed[br]to look for chemical changes

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that might inform the oncologist[br]about the best course of treatment.

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And what was discovered[br]from studies like that

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is that the sugars have changed

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when the cell transforms[br]from being healthy to being sick.

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And those correlations have come up[br]again and again and again.

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But a big question in the field[br]has been: Why?

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Why do cancers have different sugars?[br]What's the importance of that?

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Why does it happen, and what[br]can we do about it if it does turn out

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to be related to the disease process?

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So, one of the changes that we study

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is an increase in the density[br]of a particular sugar

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that's called sialic acid.

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And I think this is going to be[br]one of the most important sugars

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of our times,

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so I would encourage everybody[br]to get familiar with this word.

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Sialic acid is not[br]the kind of sugar that we eat.

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Those are different sugars.

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This is a kind of sugar[br]that is actually found

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at certain levels on all[br]of the cells in your body.

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It's actually quite common on your cells.

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But for some reason,

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cancer cells, at least in a successful,[br]progressive disease,

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tend to have more sialic acid

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than a normal, healthy cell would have.

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And why?

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What does that mean?

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Well, what we've learned

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is that it has to do[br]with your immune system.

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So let me tell you a little bit[br]about the importance of your immune system

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in cancer.

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And this is something that's, I think,[br]in the news a lot these days.

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You know, people are starting[br]to become familiar with the term

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"cancer immune therapy."

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And some of you might even know people

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who are benefiting from these very new[br]ways of treating cancer.

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What we now know[br]is that your immune cells,

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which are the white blood cells[br]coursing through your bloodstream,

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protect you on a daily basis[br]from things gone bad --

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including cancer.

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And so in this picture,

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those little green balls[br]are your immune cells,

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and that big pink cell is a cancer cell.

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And these immune cells go around[br]and taste all the cells in your body.

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That's their job.

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And most of the time, the cells taste OK.

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But once in a while,[br]a cell might taste bad.

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Hopefully, that's the cancer cell,

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and when those immune cells[br]get the bad taste,

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they launch an all-out strike[br]and kill those cells.

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So we know that.

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We also know that if you can[br]potentiate that tasting,

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if you can encourage those immune cells[br]to actually take a big old bite

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out of a cancer cell,

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you get a better job protecting[br]yourself from cancer every day

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and maybe even curing a cancer.

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And there are now a couple of drugs[br]out there in the market

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that are used to treat cancer patients

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that act exactly by this process.

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They activate the immune system

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so that the immune system[br]can be more vigorous

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in protecting us from cancer.

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In fact, one of those drugs

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may well have spared[br]President Jimmy Carter's life.

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Do you remember, President Carter[br]had malignant melanoma

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that had metastasized to his brain,

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and that diagnosis is one[br]that is usually accompanied by numbers

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like "months to live."

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But he was treated with one[br]of these new immune-stimulating drugs,

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and now his melanoma[br]appears to be in remission,

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which is remarkable,

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considering the situation[br]only a few years ago.

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In fact, it's so remarkable

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that provocative statements like this one:

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"Cancer is having a penicillin moment,"[br]people are saying,

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with these new immune therapy drugs.

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I mean, that's an incredibly bold thing[br]to say about a disease

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which we've been fighting for a long time

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and mostly losing the battle with.

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So this is very exciting.

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Now what does this have to do with sugars?

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Well, I'll tell you what we've learned.

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When an immune cell snuggles[br]up against a cancer cell to take a taste,

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it's looking for signs of disease,

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and if it finds those signs,

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the cell gets activated and it launches[br]a missile strike and kills the cell.

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But if that cancer cell has a dense forest[br]of that sugar, sialic acid,

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well, it starts to taste pretty good.

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And there's a protein on immune cells[br]that grabs the sialic acid,

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and if that protein[br]gets held at that synapse

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between the immune cell[br]and the cancer cell,

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it puts that immune cell to sleep.

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The sialic acids are telling[br]the immune cell,

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"Hey, this cell's all right.[br]Nothing to see here, move along.

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Look somewhere else."

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So in other words,

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as long as our cells are wearing[br]a thick coat of sialic acid,

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they look fabulous, right?

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It's amazing.

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And what if you could strip off that coat

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and take that sugar away?

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Well, your immune system

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might be able to see that cancer cell[br]for what it really is:

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something that needs to be destroyed.

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And so this is what we're doing in my lab.

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We're developing new medicines

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that are basically[br]cell-surface lawnmowers --

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molecules that go down[br]to the surface of these cancer cells

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and just cut off those sialic acids,

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so that the immune system[br]can reach its full potential

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in eliminating those cancer[br]cells from our body.

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So in closing,

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let me just remind you again:

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your cells are coated with sugars.

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The sugars are telling cells[br]around that cell

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whether the cell is good or bad.

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And that's important,

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because our immune system needs[br]to leave the good cells alone.

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Otherwise, we'd have autoimmune diseases.

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But once in a while,[br]cancers get the ability

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to express these new sugars.

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And now that we understand

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how those sugars mesmerize[br]the immune system,

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we can come up with new medicines[br]to wake up those immune cells,

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tell them, "Ignore[br]the sugars, eat the cell

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and have a delicious snack, on cancer."

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Thank you.

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(Applause)