9

In an interview on pop-sci magazine "The Scientist", Dr. Robert Austin from Princeton is asserting that:

It’s a tradeoff, he says, for the rapid evolution our species has leveraged to become the dominant force on the planet. He also suggests that cancer might act as a form of global population control, possibly serving to increase species fitness.

This does not seem sound reasoning to me - first one would need to demonstrate there is such a thing as a "speed" of evolution, and then that humans are "rapid" in some form, and finally that the cancer is somewhat related to this.

In fact, people are also skeptical in the comments, for example I read:

The type of group selection advanced by V. C. Wynne-Edwards and discussed above was discredited decades ago.

What are the facts here? Is he passing random speculation and just-so stories as facts? Is the journalist "misinterpreting"? Or he's got valid published studies behind his assertions?

  • 1
    Of course, if humans rapid evolution, due to cancer, has made us the dominant force on the planet, we'd better watch out for all the other animals who also suffer/thrive from cancer... – Oddthinking Apr 8 '13 at 3:17
  • 1
    Because cancer usually occurs beyond reproductive age, cancer doesn't play a part in the natural selection process, even if there was an advantage to it. – Kenshin Apr 8 '13 at 5:17
  • 3
    @chris - That is actually a good argument in favor of the theory, since the disadvantage (dying of cancer) is not relevant to survival of the genes, and the advantage (e.g. the genes having more variations), are. – Ofir Apr 8 '13 at 5:53
  • 2
    @chris - Cancer is a complex effect tied to cell reproduction, the mechanism that causes vulnarbility for cancer could be beneficial earlier. I doubt anyone would suggest that cancer itself is beneficial. – Ofir Apr 8 '13 at 5:58
  • 1
    Not sure this can be answered here. It’s clearly a fringe view but it’s too early to present a properly published opposition to his ideas. He does go against our current understanding of evolution (by implicitly asserting that selection happens on the species level). However, the concept of “speed of evolution” is reasonably well-defined and there’s some evidence that human evolution has accelerated over the last hundred thousand years. – Konrad Rudolph Apr 8 '13 at 9:16
2

This whole interview conveys some very strange ideas about evolution. So while I am not able to answer the question directly, I'll hope to make clear why the presented argument is on shaky grounds and hence one does not need to accept Austin's conclusion because of that.

Let's begin with Robin Austin defining what cancer is:

I have two answers. One is it may be due to a fundamental, general instability in any system which has mutations going on where you’re reproducing yourself. There’s a fundamental danger there. It’s the risk that the system is willing to accept in order to evolve.

A system is not willing to "accept" anything in order to do anything, let alone "to evolve". There is no need for livings being to evolve, no goal to be achieved. All we know is that they do, hence the variations of life.

It's true that due to the imperfect replicating process errors can lead to sicknesses, yet a necessity for such a system to be prone to cancer does not follow. There are multiple different genetic defects, why should cancer be special and intrinsic to the process?

Austin continues:

It may also be plan B in the sense that we’re supposed to age and die. It’s very important that we die. If you take good care of yourself so the normal ways of death don’t happen, the system will go ahead and turn something else on to make sure that individual ceases.

We are not supposed to do anything. Living beings simply are. We humans tend to search for meaning where there is none to be found and this seems to be one example of that.

It's neither important nor unimportant that we die. Importance is quite a strange concept to apply here.

Living beings are until they die. If they procreate before death, then their offsprings simply are, too. And what stays around, stays around. No need to die, unless you assume that evolution must happen, and that there never could occur a constant state, like a planet only being inhabited by one big immortal plant covering its entire surface.

There is no evolutionary pressure that forces livings beings to gain immortality, but that doesn't mean the individual must die within a certain time frame. (In fact, Turritopsos Nutricula might as well have evolved into something that can be deemed de-facto immortal.)

So to say that cancer is our body's mean to ensure that we die because we must die does not follow. It sounds like an ad-hoc rationalization to make sense out of a (meaningless) sickness.

It's like saying we were supposed to die of bacteria. And by that logic, the invention of antibiotics would have been a bad thing.

Furthermore, we eliminated a lot of other threats which would have killed us in the past, so there isn't much left to kill us. One remaining candidate happens to be cancer. And car accidents. And smoking. Would anybody claim that driving a car and smoking would be "the system's" means to ensure that we die someday?

TS: So, cancer is a way of killing off individuals to support survival of the species, like programmed cell death kills off certain cells within the body to support survival of the organism?

RA: Yeah, it’s apoptosis on a large scale. That’s why the immune system gives it a pass. In fact, the body might even fight your attempts to reverse the process, because it actually wants it to happen.

Evolution does not work on the species scale. Quite frankly, the individuals of the same species are their own worst enemies as they primarily compete against each other for living space, food, and mating partners. Think about a lion killing the cubs of a lonesome lioness. If evolution would favor the species, how would that have evolved? If we only look on the individual case instead, there would be no paradox.

So the individual is the agent in evolution (or more precise, as Dawkins famously argued, the selfish gene. Yet genes do not occur lonesome on this planet anymore).

Natural selection determines if the individual is fit enough to procreate in a given environment. Each living being has to procreate for their genes to "live on" or where that is not possible, (e.g. a working bee), ensure its closest relatives to live on.

TS: Are you saying that cancer is ultimately good for us? RA: Yeah, on a species level. We all know that to evolve, we must have mutations. Cancer is more prevalent in humans, because that is the mechanism driving our rapid evolution.

To say cancer is good for us on a species level is as valid as to say "the wolf that caught a slower deer is helping the deers as a species". By that logic, the caught deer must be thankful for being caught and eaten.

Yet the wolf has no intent of helping the deers as a species. It needs food to survive and does so by hunting. It happens that while hunting the wolf most likely will only catch slow and sick animals, while the others more often will escape.

Same with the cancer. It most likely "wants" nothing. It simply occurs due to "defective" genetics. Would anyone shout at the diagnosis of cancer: "Oh joy, I have cancer. My body wants to kill me to enhance the human species. How nice of my body!" I do not think so.

The damning thing about cancer is that there is no evolutionary pressure against it, as we develop its fatal symptoms mostly in our adulthood and it kills its host in relative old age long after it most likely has reproduced. (Or to say it differently: We humans did not evolve a resistance against cancer for the same reasons dinosaurs did not evolve resistance against big comets hitting the earth.)

So, is cancer a trade-off to allow for faster mutations? I do not know. Yet it is just as well conceivable that cancer occurs because of harmful mutations without any benefit from it.

(That isn't to say that there aren't some mutations that hinder old age, yet can be deemed beneficial in the sense that they allow humans to live long enough to procreate in the first place, like sickle cell anemia that lowers the risk of Malaria.)

Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.

  • 2
    We require answers to reference every significant claim they make, could you please add some references to support your most important conclusions here? – Mad Scientist Apr 9 '13 at 14:39
  • Welcome to Skeptics! Please provide some references to support your claims. – Larian LeQuella Apr 10 '13 at 0:59
  • Please note that using imprecise wordings like anthropomorphising systems and such is not ALWAYS a sign of not understanding how evolution works. Dawkings himself does that at times, on purpose, as a device to simplify the narrative and increase ease of understanding (not claiming that this is what happens here as I didn't bother reading quoted details, but be aware that critiquing a scientific idea over layman-level presentation of it isn't the most soundest of critique). – user5341 Apr 16 '13 at 22:23

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .