Thursday, July 31, 2008

Evolution: Cancer and Genetic Disorders

I've been watching House a lot over the past few weeks. As I've listened to their method of diagnosis and read about the terms and diseases they discuss a question has formed. So, let's talk about what a few words mean.

Evolution: While the definition of Evolution is articulated differently depending upon the particular source of the definition its core is that "Evolution" is the concept of replication with change. A species or class or type changes over time, mutates over time, and those changes and mutations are passed along through various particular manifestations of a species or class or type via, in biology, its genes.

Cancer: Cancer is the term used to denote a class of malignant Neoplasms or "growths". While Carcinogens promote the propagation of Cancers a particular organism's response to exposure to a carcinogen will be influenced by that particular organism’s inherited traits of susceptibility, its genes.

Genetic Disorder: A Genetic Disorder is a detrimental abnormality in a particular organism which results from an abnormality in its chromosomes or genes.

Here's my poorly worded, unnuanced question: Are not Genetic Disorders and Cancer particular manifestations of the core concept of Evolution? Are not Genetic Disorders and Cancer the result of that which occurs in the process denoted by the word "Evolution"?

For the moment let's abandon the social implications or understandings of these concepts and rather assess these concepts without bias. The idea of Evolution is that fundamental structures of life change over time. For example, the finches Darwin observed are said to be related but not identical. Each particular manifestation of a finch was an example of a modification to the larger category of "finch". How are Genetic Disorders and Cancer in human beings not the human equivalent of a change to beak structure?

Evolution is not sentient, not a god-esque force in Nature making decisions and assessing merits. Evolution is change; unbiased, unencumbered change. Darwin noted that species which evolve to have characteristics which are detrimental to survival die off whereas species which evolve to have useful characteristics thrive. But evolution does not make a conscious decision of "detrimental" or "useful". Evolution is merely change. Reality is where those characteristics play themselves out and "detrimental" or "useful" is observed based upon the impact a particular mutation has on an organism's survivability.

When you think about it? Cancer and Genetic Disorders are instances of Evolution, of that tendency for mutation which is a fundamental component of life within this reality. Treating Cancer, treating Genetic Disorders, is really an attempt to treat Evolution. Yes, in some instances doctors treat the result of evolution. But in others? They are attempting to treat evolution itself, to take particular biological instances of Huntington's Chorea and somehow modify these results of Evolution to not have that which they have evolved to have.

While we could focus on the boring, arbitrary conversation of whether or not treating these "diseases" is right or wrong, beneficial or detrimental, it would be more interesting to assess whether or not I am correct. Are Cancer and Genetic Disorders part of the process of Evolution? Are not these changes and mutation merely the result of the facticity of the reality in which we live, that fundamental process which occurs in the reproduction of the species? Evolution is replication with change. Are not Cancer and Genetic Disorders little more than that replication with change? Are not Cancer and Genetic Disorders the sorts of things which occur through Evolution?

12 comments:

_J_ said...

If Cancer and Genetic Disorders are a part of the process of evolution then, really, that undermines the classification of these conditions as "diseases".

Diseases have the characteristics of abnormal, disorder, error, special condition, etc. Disease is contrary to normalcy.

BUT if evolution is normalcy, if change is normalcy, then we have to reconsider our concept of normalcy.

If humanity exists in stasis, if the replication of the species is limited to exact, carbon copies throughout the generations? Then changes to those carbon copies can be held to be out of place or not normal. But if human beings as a species are subject to evolution (as all living things are) then there is no such thing as an established, static "normalcy" for what a human being is. Normalcy, rather, would be that constant change.

So an accurate portrayal of reality would acknowledge the fundamental change which occurs in life (called "evolution") and abandon this sort of Platonic Ideal of what a Human Being is given that the Ideal would have to be classified as a social construct given that it has no basis in reality.

kylebrown said...

Genetic disorders are evolution in the works. Cancer is not. Cancer is not defined in our genes. Susceptibility to certain cancers can be, but cancer is an acquired disease, and therefore can not be evolution. One does not pass cancer on to their children.

And why can't we call them diseases? Disease normally means that part of the body is functioning incorrectly, and most genetic disorders are exactly that, maladies that cause organs to function incorrectly. And cancer is by definition a disease.

_J_ said...

"Susceptibility to certain cancers can be, but cancer is an acquired disease, and therefore can not be evolution."

This one was tricky. Cancer is neither 100% genetic nor 100% acquired. Fetuses can get cancer as a result of their genes. Human beings can get cancer from exposure to carcinogens. But in both cases one's genes impact the acquisition of cancer. Some people are more or less immune to cancer due to their genes.

That component of cancer is the result of evolution, the passing along of those genes which are more or less susceptible to cancer.

A the genes of a person who gets cancer are less resistant to cancer than a person who does not get cancer, when viewing cancer from an environmental perspective.

"Disease normally means that part of the body is functioning incorrectly, and most genetic disorders are exactly that, maladies that cause organs to function incorrectly."

That's the point, though. For something to be "incorrect" there must be a "correct". Once we recognize that life is itself subject to evolution, constant mutation and change, there is no definition of "correct" any longer. Since everything mutates and changes there is no permanence from which "correct" can be defined.

If we say that a certain part of the body is "functioning incorrectly" we have to appeal to a notion of what it is to "function correctly". That does not exist if life is itself constantly changing and mutating.

We CAN say that a particular instance of a particular thing is detrimental to the survival of a particular life. But that's not what diseases are. "Diseases", as a concept, appeals to a notion of normalcy which does not exist once we realize that humanity is subject to evolution and so constantly mutates and changes.

_J_ said...

"Cancer is not defined in our genes."

I think some are and some are not.

Obviously the genetic ones would fit into the "evolution" discussion. Go go retinoblastoma.

The ones that aren't are a question of susceptibility. That's, again, genetic.

kylebrown said...

"Fetuses can get cancer as a result of their genes."

It is faulty to say these cancers are the result of their genes. The fact of the matter is in the extremely rare case that a parent passes their cancer to their child, we still don't understand how it happens, but it is most likely the case the cancer spreads to the fetus the same way cancer's spread throughout the host body.

The same can be said for HIV, it is passed on through birth, does that make it evolution? Of course not.


The cancers with hereditary components are not themselves hereditary, they are the effect of a different cause, which can be attributed to genetics. I said this already whne I stated, "Susceptibility to certain cancers can be..." The cancer itself is not evolution.

_J_ said...

"It is faulty to say these cancers are the result of their genes."

Retinoblastoma is the result of a defective gene passed on from parents to children. Retinoblastoma does not result from a carcinogen or other toxin. Retinoblastoma is the result of a defective gene passed from parents to children.

"The cancers with hereditary components are not themselves hereditary, they are the effect of a different cause, which can be attributed to genetics."

If the cause is genetic (retinoblastoma) and its passing is hereditary...that's the definition of the core concept of evolution. Mutations occur in genes and those genes are passed on to offspring. The retinoblastoma protein is a gene which has mutation, the mutation of which results in retinoblastoma.

"The cancer itself is not evolution."

Certainly a particular instance of cancer is not a particular instance of evolution, neither cancer nor evolution work that way. But retinoblastoma is the result of evolution, genetic mutation, and it's passing s hereditary, which is how evolutional changes are passed.

Given that retinoblastoma is the result of a gene mutation and its passing is hereditary I would think it very difficult to say retinoblastoma is notthe result of those genetic mutations which occur through the process of evolution.

"The same can be said for HIV, it is passed on through birth, does that make it evolution? Of course not."

I'll agree that the passing of HIV is not an evolutionary process given that HIV is the passing of an infection and evolution is the passing of genes. But a disease like retinoblastoma which is the passing of mutated genes? That's the core concept of Evolution.

kylebrown said...

The mutated genes are not the cancer. The mutated genes stifle the development of a certain protein which suppresses cancer. You are skipping a very important step.

Immunodeficiency can often times be genetic. Does this mean that when someone with a hereditary immunodeficiency disorder gets a cold, that cold was genetic?

Retinoblastoma is no different. Retinoblastoma is a disorder in which a disease suppresent fails due to gentetic factors. The cancer that results because the protein that would normally suppress it does not exist, is not genetic, it is merely an effect of a genetic cause.

_J_ said...

"The cancer that results because the protein that would normally suppress it does not exist, is not genetic, it is merely an effect of a genetic cause."

So retinoblastoma is not genetic. The cause of retinoblastoma is genetic but retinoblastoma itself is not...

True. AND more accurate and precise.

So that means that when we talk about evolution the conversation can only be of genes, since evolution is only the system of genetic mutation and its being passed along.

So, really, we can't talk about genetic disorders and evolution. Rather, we have to talk about the specific genetic situations of those disorders. The disorders themselves are not passed along. Only the genetic structures which cause them.

Hmm.

That means that Darwin talking about finches was misleading. The different finch structures were the result of those evolutionary changes, not the evolutionary changes themself.

Hmm.

kylebrown said...

I'm going to say this one more time:

"Genetic disorders are evolution in the works. Cancer is not. Cancer is not defined in our genes. Susceptibility to certain cancers can be, but cancer is an acquired disease, and therefore can not be evolution."

The disorder associated with the protein that suppress Retinoblastoma is an evolution. The Retinoblastoma itself is not. Direct effects of changes in the genes can be considered evolution, but the side effects, if you will, are not evolution.

Sickle Cell is a good example of this. The sickllng of the cells is an evolution, to fend off Malaria. Complications arrising from the sickling of the cells are not evolution, they are effects of the evolution.

The bigger question is how we as a society are affecting evolution by helping people survive maladies they would not otherwise survive without modern medicine. We could very well be breeding some of the hardiest of our genes out of the general population, as people with genetic disorders are capable of lviing to reproductive age, when they would otherwise not be able to without medicine.

_J_ said...

"Direct effects of changes in the genes can be considered evolution, but the side effects, if you will, are not evolution.
"

That's where I seem to not be understanding you. I would consider the retinoblastoma to be a direct effect of the evolution. The gene mutation is in the gene which prevents retinoblastoma, as I understand it. Since the gene is not there to prevent it then it occurs.

I'm not understanding how you distinguish a "direct effect" from a "side effect". Mostly because the only "direct effect" in evolution is the actual mutation of the gene.

The causal chain for all of this is pretty wonky. Genes to development of cells to cell growth/life to cell death.

I guess I don't understand the scope of how we're considering these things. Micro vs. Macro and which Macro result.

"The bigger question is how we as a society are affecting evolution by helping people survive maladies they would not otherwise survive without modern medicine."

I tend to shy away from that question and favor looking at how society thinks of these things and reacts to them. When one considers that the mutation of genes is something which occurs in this reality it greatly impacts our definition of "normal" and "disease" and the whole medical field when considering these results of those mutations.

We've taken the stance that these mutations are detrimental to particulars and as a result have fucked over the whole by fostering an approach which attempts to offset evolution by medicating it.

That's just absurd.

kylebrown said...

I'm curious why the tumor suppressant is necessary in the eye and nowhere else in the body. if it is a case of the cells there just naturally grow unchecked or if it is the result of outside influences (light, UV) being a carcinogen to the cells. You may be correct in this case that the cancer is hereditary, in that it is hereditary in all of us, but the majority of us just happen to have a working suppressant to subdue it.

_J_ said...

"in that it is hereditary in all of us, but the majority of us just happen to have a working suppressant to subdue it."

Yeah. The way it's presented on a few sites it sounds like those cells just continue to replicate and that gene stops the replication at some point.

Which is hella odd.

I can only assume that every part of human anatomy operates in this same way. That being said, they need to find the gene that stops penis growth.