Medical Cancer and Evolution: Understanding the Connection and Dispelling Misconceptions

[Pythagorean]

The source is lost to me now, but I remember hearing that cancer and evolution (and even radioactive mutation) are all the same physical process, and that the difference between them is human conception.

That is, if the changes result in what was see as a benefit, we call it evolution, but if it results in a useless augmentation, we call it mutation.

Any experts or pseudo-experts (students) that can clear this up?

 

[Rade]

There is no relationship of cancer (a process of cells) with evolution (a process of species). All species undergoing evolution would be expected to have some individuals die of cancer. But you also include mutation, which of course is related to both cancer and evolution. Here are the relationships between the three:
faulty mutation = cancer
adaptive mutation = evolution
Your concept of faulty evolution is called extinction.

 

[DaveC426913]

faulty mutation = cancer

I think this is what he was trying to say.

 

[Pythagorean]

I think this is what he was trying to say.

indeed. Thank you for your responses

 

[Phobos]

just to confuse the issue, try this...
http://scienceblogs.com/loom/2006/08/09/an_old_dog_lives_on_inside_new.php
(cancer tumor becoming a new lifeform?)

 

[jxs919]

faulty mutation = cancer
adaptive mutation = evolution

i'd have to agree with that.

 

[Phobos]

faulty mutation = cancer

Only if it causes an out-of-control cell growth, yes? Some mutations have no effect.

 

[nipwoni]

Seems to me that cancer and evolution are related in a way. Cancer cells are better at surviving and reproducing than other cells, because they've escaped the body's controls on cell division. This allows them to increase their population much faster than other cells. They have adaptations to help them survive, like the ability to grow in huge masses without contact inhibition, the ability to induce capillaries to grow towards them and provide them with a blood supply, the ability to metastasize, etc. This is "survival of the fittest" too. Unfortunately this is not adaptive for the organism as a whole, so it's only fit in the short term. Long ago we were unicellular, but then cells started living together as multicellular beings, so they had to find ways to get along. But you can always expect some "selfish" cells to find ways around that, like selfish individuals in a society.

 

[nipwoni]

I also think all mutations are "faulty." Some of them just happen to have benficial effects.

 

[Another God]

Seems to me that cancer and evolution are related in a way. Cancer cells are better at surviving and reproducing than other cells, because they've escaped the body's controls on cell division. This allows them to increase their population much faster than other cells.

But it also does so at the expense of the body, on which those cells are dependent. Its like any parasite which kills its host, it is likely to cause its own extinction.

They have adaptations to help them survive, like the ability to grow in huge masses without contact inhibition, the ability to induce capillaries to grow towards them and provide them with a blood supply, the ability to metastasize, etc. This is "survival of the fittest" too. Unfortunately this is not adaptive for the organism as a whole, so it's only fit in the short term. Long ago we were unicellular, but then cells started living together as multicellular beings, so they had to find ways to get along. But you can always expect some "selfish" cells to find ways around that, like selfish individuals in a society.

Ahh yes, maybe i should have finished reading your post :)



In a way you can call anything evolution which displays variation in a generational replication under the force of selection. Every single cell in our body may 'evolve', but selection quickly culls the 99.9...% of the mutations because they are 1. Inappropriate for a multicellular organism, 2. They aren't the germ cells and so never survive longer than max 100 years.

So from an extreme point of view, sure, cancer cells have evolved, and have been or are being selected against
(they are always counter adaptive). But more commonly we only think of thinigs 'evolving' when they mutate into something beneficial in the long term. And I think the long term (thousands+ of generations) is the really important bit. With that consideration, no somatic cell mutation will ever be considered to have 'evolved', because it has no long term affect.

 

[jxs919]

cancer is faulty evolution. you get cancer when defective genes express defective proteins that cause uncontrollable cellular prolifration.

that is cancer. whether its gettin you skin mutated by the sun or havin a genetic predisposition.. both lead to it.

 

[Phobos]

cancer is faulty evolution.

Not quite. Individuals do not evolve. Populations do.

 

[Couperin]

The source is lost to me now, but I remember hearing that cancer and evolution (and even radioactive mutation) are all the same physical process, and that the difference between them is human conception.

That is, if the changes result in what was see as a benefit, we call it evolution, but if it results in a useless augmentation, we call it mutation.

Any experts or pseudo-experts (students) that can clear this up?

Both positive and benign mutations are referred to as mutations. 5 million years ago, chimp-like animals were born with mutated skull structures, and these mutants eventually went on to become humans.

So cancer isn't really evolution 'going wrong'. Consider this: A human is born with a disposition toward developing cancer, and later in life the human develops cancer and dies. But if the human managed to have children before they died, then evolution hasn't 'gone wrong' in a survival-of-the-fittest sense.

Cancer itself isn't really an example of evolution (AFAIK). Cells inside the human body just start reproducing wildly, but the cancer cells aren't undergoing any mutations or adaptations in the way that a virus might. I could be wrong.