Science Talk

The Inevitability Of Cancer's Commonality; and High School Math Whiz

In this episode, author and journalist Carl Zimmer talks about his Scientific American article Evolved For Cancer?, which looks at how natural selection has led to what appears to be an inevitable tendency for human beings to develop the disease. Dmitry Vaintrob, winner of the 2006-07 Siemens Competition in Math, Science and Technology for high school students, talks about his project in string topology. Plus we'll test your knowledge about some recent science in the news. Websites mentioned on this episode include;;

Steve: Welcome to the Science Talk, the weekly podcast of Scientific American for the seven days starting January 10th. I am Steve Mirsky. This week on the podcast high-schooler Dmitry Vaintrob talks about his mathematical project that recently won the annual Siemens Competition in Math, Science, and Technology, and that comes with a $100,000 dollar scholarship. We will test your knowledge about some recent science in the news and first up, author and journalist Carl Zimmer. He wrote the article, "Evolved for Cancer?" in the January issue of Scientific American. To find out more about why cancer may be an unavoidable part of being human, I called Carl at his home in Gilford, Connecticut.

Steve: Hey Carl, how are you?

Carl: Good Steve. How are you?

Steve: I am pretty good. You have this article in the current Scientific American. You have a quote in the article, "in one sense cancer is a side effect of evolution." So, that's pretty interesting. What exactly does it mean?

Carl: Well, it means that the way that our bodies are built and the way that they have evolved makes cancer almost an inevitable by-product. We have these big bodies made up of trillions of cells and they are only going to work if they all cooperate. If the cells all do what they are supposed to do—and the problem is that every time a cell divides, there is a small chance that it might mutate. In some cases, though, its mutation may lead to cancer, and so, you know, the fact, unless we want to be just single-celled creatures, we are going to have to grapple with cancer as part of our evolutionary heritage.

Steve: Yeah, I prefer to be a multicellular organism. (laughs) So why does natural selection not weed cancer out if it's such a detrimental, you know, entity among us humans?

Carl: Yeah, we like to think of our natural selection as being this all-perfect force, this thing that can basically make everything great, and that's just not how natural selection works. It can produce some complex organs, like the eye, for example, but it has its limits, and part of the problem is that natural selection forces [a] trade-off. So if there is a strategy that boosts your chances of survival against one threat, it might make you more vulnerable to another threat. So, for example, we actually have defenses against cancer. We have genes that make proteins that act through like gatekeepers and they sort of monitor our cells and make sure that they are not starting to grow out of control, and if those cells do grow out of control, they get killed or they just kind of go into an early old age and they stop reproducing. The problem is that this can be very damaging and can actually be bad for overall health. I mean, if these proteins get too active, there are a lot of bad things that they can do. So there is only so much there that we can rely on those proteins to protect us, and so some cancer is going to get through as a result. There is just this balance there that natural selection has to negotiate.

Steve: You talk in the article about some mice studies, in which the genes for tumor suppression are turned off and there are actually some really good effects of that.

Carl: Yeah, these are genes that have been identified as being really crucial in protecting us from cancer. So now you think that that they would just be pure good. I mean, these are the genes that you want to have and if you get rid of them, there ought to be a complete catastrophe. Well, if you turn off some of these genes—and scientists have done this in mice—it is true that that they suffer more from cancer, but on the other hand they are also able to bounce back from other kinds of disease and such. So, for example, these scientists took these mice and destroyed the cells in their pancreas that make insulin. Basically, they gave these mice diabetes and these mice were able to very quickly regenerate the cells they needed to make more insulin and to basically kind of cut down on the diabetes they were suffering from, whereas with normal mice, which had the working versions of these genes for fighting cancer, their diabetes got so bad that sometimes they died. So, again, we are facing this tradeoff: If you want to be protected against cancer, you may become more vulnerable to other diseases and natural selection is just, kind of have to find a balance.

Steve: You also talk in the article about the really interesting history in our species of this gene for fatty acid synthase. You want to go through that? Because that's another example of these kinds of tradeoffs that evolution has to deal with.

Carl: Yeah, fatty acid synthase is a gene that helps to build membranes in our cells, and it appears that it evolved very quickly in our own lineage after our ancestors branched off from chimpanzees. It went through a really rapid evolution and some scientists suspect that it may have been involved in evolution of the human brain, which is obviously really unique compared to other primates. So there may have been something involved in making our brains, you know, run faster for example, because of the way the membranes of the neurons are built. The problem is that this gene is also really handy for cancer cells. They somehow are able to use it to get more energy, because cancer cells are reproducing really quickly and they need a lot of energy to do that and the more energy they can get, the faster they can grow. And they seem to basically borrow this gene, this gene which may have helped to make us uniquely human. They borrow that gene. I mean, if you interfere with it in a cancer cell, you may be able to kill the cancer cell. That is how important it is. So, again, you know evolution may give with one end and take away with the other.

Steve: I am reminded of the scene in Blade Runner just before Rutger Hauer digs his thumbs into his creator's eyeballs, and the creator of the—I forgot what they are called, the replicants, I think—is explaining to him all the things that they try to do to extend their life span, but the roadblocks that they ran up against in each case … but let's not hear all that.

Carl: Well, it does bring up the fact that, I mean, cancer is a horrible disease. All of us who have seen a loved one die in of cancer just can't help but hate it and want to see if there [might] be a cure for it, and so it is a pretty grim thought that somehow evolution may be either preventing cancer from being eliminated or in some cases, in some strange ways, promoting it.

Steve: Promoting it, yeah.

Carl: Plus, you know, evolution is not about making us happy and the fact is that cancer is generally the disease of the old, and in a sense what has happened is evolution has pushed off a lot of cancers to our old age and, you know, it is a horrible thing to die of cancer at any age, but if you are dying of cancer long after your reproductive years, natural selection is basically blind of to that. It does not enter into the books. So, you know, we just have to deal with what evolution has given us.

Steve: Some cancer researchers may think that thinking about these issues from an evolutionary perspective is interesting but not necessarily fruitful. So what's the reaction to that kind of thinking?

Carl: Yeah, as I was working on this article, I called up some cancer biologists to just get a sense of what they thought of all this, and so "long cancer biology" is a very new way of thinking. They are very much focused on particular mechanism[s]: okay, what protein is allowing this tumor to proliferate and to get blood vessel[s] to come to it and feed it. They are really down there in the nuts and bolts of cancer. These evolutionary biologists are taking a really long view. You know, they are thinking in terms of millions or hundreds of millions of years and processes that are going on, on a totally different time scale. And so they feel in some cases while, like, this is interesting, but, you know, what's it going to do for me, you know, right here, right now, in the lab? And I think, though, that that there are some cancer biologists who are starting to see that there may be some very particular way in which this kind of perspective from evolution may be able to help them. So, for example, it may be able to help them pinpoint a specific gene that may be playing a really important role in cancer that might not have otherwise been noticed, and it may help them to understand what are the particular pressures that are in driving a gene to evolve in a certain way that's favored by natural selection that might also make them serve as a better weapon for a cancer cell. So, you know, it's the early days yet and there is a lot of skepticism, healthy skepticism, but there is also sort of a meeting of two cultures: the cancer biologists and the evolutionary biologists, and there's really a need to sort of see that happening right at the beginning.

Steve: The article is "Evolved for Cancer?" in the January Scientific American, and in the author's box it says that you are working on a new book about E coli and the meaning of life. Is that right?

Carl: Yeah, I have been getting really interested in how biologists think about what it means to be alive, just the most basic question that biology can ask, and it's kind of a crazy question to investigate in a book and the best way I found to sort of constrain it is to look at one thing, and so I decided to pick the thing that scientists know best and that's E coli. I mean, basically it is the one thing that more than anything made molecular biology possible, and this there's a huge amount of research going on it now.

Steve: And when does that book come out?

Carl: Well, some time in 2008. We haven't decided exactly when.

Steve: Have you finished writing it?

Carl: I just did.

Steve: Oh, good for you. Carl, great to talk to you. Thanks very much.

Carl: Thanks a lot, Steve.

Steve: Carl Zimmer's article is also available at our Web site, and check out a lot of his writing at his Web site

Now it's time to play TOTALL.......Y BOGUS. Here are four science stories. Only three are true. See if you know which story is TOTALL.......Y BOGUS.

Story number 1: The American Dialect Society choice as word of the year for 2006 is "plutoed."

Story number 2: Tucson's toilets are being visited by what appear to be white rats, like those sold as pets or found in labs.

Story number 3: Americans get 8 percent of their calories from liquids rather than from foods that you chew.

Story number 4: One scientist thinks we may already have stumbled upon life on Mars and killed it.

We will be back with the answer. But first, last month Dmitry Vaintrob won the prestigious Siemens Competition in Math, Science, and Technology for high school students for his project involving something called string topology. One of the judges, Harvard mathematician Michael Hopkins, said that Vaintrob found a very beautiful formula for describing the way shapes combine in string theory. He also said the work was at the doctoral level already and was already attracting a lot of attention. To find out more I called Dmitry at his home at [in] Eugene, Oregon.

Steve: Hi Dmitry, how are you?

Dmitry: Hi Steve, I am fine. Thanks.

Steve: Congratulations on winning the Siemens competition.

Dmitry: Oh, thank you.

Steve: And the $100,000 dollars that goes along with it. I am sure that will come in handy.

Dmitry: Yeah, that is very nice.

Steve: So, Dmitry, how old are you?

Dmitry: I am 18.

Steve: And are you graduating from high school this year?

Dmitry: Yeah, I am a senior this year, yeah.

Steve: When did you first realize that you had a talent for mathematics?

Dmitry: I don’t know. I have been interested in math for as long as I can remember, and I have always asked my dad lots of questions about math because my dad is a mathematician. So I had asked questions, I guess, about not only math, but physics and pretty much anything I could think of, but questions, my dad could answer, the math questions best.

Steve: So, that was the dinner table conversation in your household?

Dmitry: Yeah, that was the dinner table conversation, except for those before my sister at once….

Steve: Is she good at math, too?

Dmitry: My sister? Yeah, she is very good at math, yeah, but she doesn't really understand the idea of spending dinner talking about math.

Steve: Well, how old is she?

Dmitry: She is eight. (laughs)

Steve: She is eight, okay.

Dmitry: And she is an artist.

Steve: And what does your mom do?

Dmitry: She has been a poet and a writer, and now she teaches in the university. She teaches Russian culture and literature.

Steve: So did your talent for mathematics, did it exhibit itself at an early age? Do you remember any incidents when you were a little kid where you just noticed things mathematically that other people might not have noticed?

Dmitry: Oh yeah. My dad gave me a problem. So I guess I had the opportunity to think about math a lot earlier than other kids. So, I guess, I remember at some point, I guess, when I was maybe eight like my sister. So my dad told me the Pythagoras theorem that for [a] triangle with a right angle, the sum of squares of two sides is equal to the third side, and so he told me that sometimes that the triangle can have interdealing, so sometimes you can have, say, three squared plus four squared is equal to five squared.

Steve: Right.

Dmitry: These are called Pythagorean triple. He gave me a chance to find as many triples as I can. And so I started thinking about triples and I found a few. So if you have a triple, then if they double all the sides and you have another triple. So it's easy to get as many triples as you like, thereafter an infinite number of triples this way. So my dad gave me this choice to find [an] infinite number of triples that aren't multiples to each other. So, I remember I thought [about] that for a while and then I came up with this one way to get [an] infinite number of triples, and I think that is, I guess, my first time I can remember when I was very excited about coming over such thing in math.

Steve: Do you think you can explain to a person who might have trouble balancing their check book what your winning project was about?

Dmitry: I could try, yeah. My project was in a field called topology, and so this is actually a field of math that does not study numbers—as many people describe that math is a study of numbers—but topology actually is a study of shape. So even though we think in three dimensional, but we know that we live on a sphere, and since we are very, very small and the sphere is very big, it looks as if the sphere is flat. So, because everywhere locally that it looks flat, this is called two dimensional. So, how come you find out the fact that the earth isn't just a plane? Well, one way to do this is to do what Magellan did and to go on a trip around the world.

Steve: To arrive at up exactly where you started, it has to be a sphere or at least some kind a shapethat'sq

Dmitry: And so you can't do that on a plane.

Steve: It could be a cylinder, but it is certainly not a plane.

Dmitry: So, this showed that the earth is topologically not a plane and so the way he showed it was by making a loop around the earth.

Steve: That takes a lot of time and energy and you have to have a whole crew of people to run your ships.

Dmitry: Yeah, exactly.

Steve: But you're working on, you know, in a much more elegant environment where you are thinking about it.

Dmitry: Right, yeah. I can't get a crew to go around the world, yeah. And so there are also other constructions you can do it with. So one of them is called string topology. So this is actually one: Instead of having single loops you have families of lots of loops that you can also sort of multiply. And so string topology was actually discovered just a few years ago in 1999 and, I guess, it is sort of motivated by physics and string theory, and so it is related to physics. So the form of string topology is that to compute it where most shapes, even for surfaces, it is very hard because in a way there is[are] lots and lots of differences. And so what I did in my project is I showed that for a certain shape, two-dimensional shapes and also higher-dimensional shapes, this string topology can actually be computed using abstract construction from this much more, I guess, easy to compute or easier to work with construction called the fundamental group. They say that this construction of the constant described in math is called as abstract algebra. So this abstraction is the same as construction history of string topology. So, I guess I related these subjects in different fields, and I still think for certain shapes that actually are the same.

Steve: And this could have some applications in actual real-world physics or just in string theory or …

Dmitry: I guess whenever you do something in math or in physics, you really never know what sort of applications you can have. Of course, I don't know of any immediate applications in physics and I don't know physics well enough to think of any.

Steve: But it would not be surprising if 10 years from now somebody winds up using the system that you came up with to do something in the real world.

Dmitry: I think that’s possible, either this or something that comes out of it, because also, not whenever you prove something there is usually something else, but this helps part of it either directly or indirectly.

Steve: Well, Dmitry, it has been a pleasure talking to you and best of luck in college and dos svidanya.

Dmitry: Poka


For more on Vaintrob and the Siemens competition go to

Now it's time to see which story was totally bogus. Let's review the four stories.

Story number 1: The official word of the year is "plutoed."

Story number 2: White rats are showing up in the toilets of Tucson.

Story number 3: Americans get 8 percent of their calories from liquids.

Story number 4: Scientists think our probes might have killed Martian bacteria.

Time's up.

Story number 1 is true. The American Dialect Society picked "plutoed" as its word of the year. "Plutoed," as you've probably figured out, means to be demoted. So, Pluto, any chance you're going to be cleaning out that desk soon? To hear the entire Pluto meets office space bit, check out the end of the August 30th edition of Science Talk at

Story number 2 is true. White rats are plaguing Tucson's toilets. The nearby Arizona Health Science[s] Center says their procedures make it impossible that the rats originated there. That's according to the Associated Press, which also quoted the local health department's unnecessary advice: it's best not to handle a toilet rat. I've heard stories of rats, perhaps from Tucson, popping out of fifth floor toilets in New York City. I knew I should have taken a toilet at Albuquerque.

Story number 4 is true. A few researchers think that microbial life on Mars might be different because of the different conditions there and that we might have inadvertently killed them when the Viking probes of the 1970s looked for life there—some of them, not all of them. The idea was presented Sunday at the meeting of the American Astronomical Society in Seattle. The internal fluid of Martian microbes might be a mix of water and hydrogen peroxide, the researchers conjecture, so that it stays liquid at the low temperatures there and the kind of tests the Viking probes did, like heating or wetting the soil, could have been deadly to any peroxide-based bacteria. I claim this planet in the name of Mars. Oh, isn't that lovely?

All of which means that story number 3 about 8 percent of Americans' caloric intake coming from liquids is TOTALL.......Y BOGUS, because in fact we get 22 percent of our calories from liquids, sodas, sugared coffee and tea, milk, etcetera. For more, check out the story on our Web site entitled "Liquids Make up 22 Percent of American Diet."

Well that's it for this edition of the weekly Scientific American podcast. You can write to us at Check out news or articles at our Web site, and the daily SciAm podcast 60-Second Science is at the Web site and over at iTunes. For Science Talk, the weekly podcast of Scientific American, I am Steve Mirsky. Thanks for clicking on us.

Web sites mentioned on this episode include,, and


Share this Article:


You must sign in or register as a member to submit a comment.

Starting Thanksgiving

Enter code: HOLIDAY 2015
at checkout

Get 20% off now! >


Email this Article