Why do the majority of people never get cancer?

Jan 22, 2009 By Lisa Zyga feature
Dividing Cancer Cells. Credit: University of Birmingham

(PhysOrg.com) -- Every year, millions of people are diagnosed with cancer - a remarkably high number. But what about the flipside of those statistics? That is, two out of three people never get cancer, and more than half of heavy smokers don’t get cancer, either. A recent study points out this overlooked fact, and suggests that researchers might discover something by asking why so many people are resistant to the often deadly disease.

George Klein, Professor Emeritus at the Microbiology and Tumor Biology Center at the Karolinska Institute in Stockholm, Sweden, has been teaching and researching since the mid-1940s. In a recent study called “Toward a genetics of cancer resistance” published in the Proceedings of the National Academy of Sciences, Klein highlights evidence of several biological cancer resistance mechanisms that some individuals have that seem to prevent them from developing cancer. Perhaps, Klein says, there are cancer-resistant genotypes that “nip cancer in the bud” and keep most of us healthy.

As Klein explains, the suffering of cancer patients and their families has inspired most cancer researchers to focus on the genetics of cancer susceptibility. On the other hand, the genetics of cancer resistance has been largely unexplored, possibly because it is assumed to be merely the other side of the susceptibility coin. For example, if cancer is caused by mutations in genes that control cell division, then it logically seems that cancer resistance is simply a low occurrence of these mutations.

But, Klein says, maybe there is another alternative to the concept of cancer resistance. Perhaps most people have various protective mechanisms that counteract the development of cancer cells and stop the disease from progressing beyond the earliest stages.

“Cancer resistance must be investigated on its own merits,” Klein told PhysOrg.com. “It is possible and even likely that evolution has provided our species with highly efficient cancer resistance mechanisms. These may be the mechanisms that prevent most circulating, disseminated cancer cells that are found in the blood of all cancer patients to grow into metastasis, and can also nip cancerous foci (islands of cells in, for example, the prostate or the breast) in the bud, so that they do not progress.”

In a previous discussion, Klein and his coauthors identified five kinds of anticancer mechanisms. The first type is immunological, which applies to virus-associated cancers. For instance, researchers have compared the antibody responses of the squirrel monkey and the marmoset when infected with Herpesvirus saimri, a virus that is endogenous to squirrel monkeys but that the marmoset never encounters. When exposed to the virus, the marmosets, but not the squirrel monkeys, develop rapidly growing lymphomas. The researchers found a striking difference in the timing of each animal’s antibody response. In the tumor-resistant squirrel monkeys, the antibodies rose to a high level just three days after the infection, but, for the marmosets, the response took three weeks. By that time, the marmosets already had a rapidly growing virus-driven lymphoma. Research has shown that such immunological responses are influenced by genetic variation.

The second mechanism is genetic, and the most common example is DNA repair mechanisms. Studies have shown that there are individual variations in the efficiency of DNA repair, which is highlighted in cases such as the specific DNA repair deficiency called xeroderma pigmentosum. Individuals with this deficiency are highly sensitive to ultraviolet light, and even with careful protection they develop multiple skin carcinomas due to the genetic deficiency.

The third mechanism is epigenetic, which involve changes in gene expression, rather than changes in the DNA text itself. Studies have shown that when mice that carry a paternal precancerous mutation inherit a maternal imprinting defect, normal parental imprinting is impaired, which can increase the probability of cancerous development. In humans, this same imprinting defect occurs spontaneously and increases tumor incidence, affecting 10% of humans, and increasing their risk of intestinal cancer about threefold.

The last two anticancer mechanisms are intracellular and intercellular. As part of an intracellular defense, a cell can trigger apoptosis, or cell death, if it detects extensive DNA damage, so that the cell doesn’t reproduce and spread the damage. But sometimes, apoptosis isn’t triggered when it should be. For example, individuals who carry the genetically mutated tumor suppressor p53 run an increased risk of inheriting Li-Fraumeni syndrome, a rare disease in which patients develop multiple tumors.

Klein predicts that intercellular surveillance by neighboring cells, the fifth known anticancer mechanism, plays a major role in tumor resistance. Cells that are in direct physical contact with each other can detect precancerous conditions in one another, and together act as a microenvironmental control system to prevent the development and progression of unhealthy cells.

While the first four anticancer mechanisms are known to be influenced by genetic variation, little research has been performed on possible genetic or developmental variations in the efficiency of the intercellular anticancer mechanism. However, Klein mentions a group of largely forgotten experiments from the 1950s and ‘60s, where scientists crossed mouse strains that had a high incidence of cancer in a given tissue (due to inbreeding and selection for that particular type of cancer) with mice from a low incidence strain. In the experiments where they studied mammary cancer, hybrid females were taken from this case. Their own mammary glands were removed surgically. One mammary gland from the high cancer strain parent and one gland from the low cancer strain parent were then transplanted to two opposite flanks of the hybrids. Dealing with two inbred strains and their hybrid progeny, there is no problem with graft rejection, Klein explains.

It turned out that tumor incidence in the normal mammary gland derived from the high cancer parent was tenfold higher than in the mammary gland from the low cancer strain. Since both tissues were in the same host, exposed to the same hormonal and viral influences, it meant that the cancerous propensity of the high cancer strain and/or the resistance of the low cancer strain was at least partly inherited at the level of the tissue itself. This genetic difference could either act at the level of the cancer cells or at the level of their microenvironment.

Klein urges researchers to investigate this intercellular issue, along with the genetics of tumor resistance that act in multiple ways. Evolution seems to have favored some relatively common resistance genes that protect the majority of humans against cancer development. One day, finding out how nature keeps most of us cancer-free could help identify and repair specific genetic mechanisms in the large minority of individuals who do suffer from cancer. However, Klein says that it’s premature to speculate exactly how understanding genetic resistance could help people who are susceptible to cancer.

“First, it has to be shown that such protection mechanisms exist and, if so, what cellular and molecular mechanisms are responsible for them,” he said. “Only after that is clear, is it reasonable to ask whether this knowledge can be applied for the practical purpose of, for example, cancer prevention.”

More information: Klein, George. “Toward a genetics of cancer resistance.” PNAS, January 20, 2009, vol. 106, no. 3, 859-863.

Copyright 2008 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

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googleplex
3.3 / 5 (6) Jan 22, 2009
Great point.
Suprising that it had not been looked at more earlier.
Cancer is such a big issue that it will require a divide and conquer approach.
An idea i've had for many years is that there are some beneficial viruses (as opposed to pathogenic viruses). However nobody rushes to the doctor to say they feel particularly well today and has a viral analysis.
I think this is a result of modern scientific research being commercially funded. Gone are the days of eccentric scientists experimenting on their own whims. Today in the world of research funding you need to conform otherwise be ostracized as a crackpot.
gopher65
4.5 / 5 (4) Jan 22, 2009
Well googleplex, I don't know if they've identified any beneficial viruses yet, but IIRC the vast majority of viruses that live in humans are not harmful to us. Just like most bacteria that live in us are not harmful to us. They just... exist.

It would not surprise me to find out that, just like with bacteria, a small number of those non-disease causing viruses aren't just neutral, but are actively helpful.
axemaster
2.5 / 5 (8) Jan 22, 2009
"Today in the world of research funding you need to conform otherwise be ostracized as a crackpot. "

That's always been the case, in every field, not just science. Because, generally people who sound like crackpots, are crackpots.
tkjtkj
3 / 5 (2) Jan 22, 2009
I asked myself long ago, before applying to grad school, the same question and i wrote a small paper expressing my ideas. It was nice seeing that another researcher, decades later , did get the Nobel for his own related work ...
Cancer is EXTREMELY rare .. Far more rare than your own article here suggests! .. and that's the key, i believe, to how it can theoreticlly be completely prevented.
j.a. , md
freethinking
2.4 / 5 (5) Jan 22, 2009
I agree, the question, why most people don't get cancer is a great question.... I wish I could say that I thought of it first. But I will use the idea for other things from now on.

Why most girls do not get pregnant outside of wedlock?
Why do most kids graduate High School?

The idea of looking at successes is a good one.
paulthebassguy
1.1 / 5 (7) Jan 22, 2009
You know, we could spend all the effort figuring out a cure for cancer now, or we could just be patient and wait a few thousand years for Darwin to do his thing and give us natural cancer resistance.
Doug_Huffman
1 / 5 (2) Jan 22, 2009
Look into and support (radiation) hormesis if you will. There you will see some resistance!
bmcghie
1.8 / 5 (9) Jan 22, 2009
I feel like I'm missing something... is this article meant to be serious? Why DON'T we get cancer? Really? Any idiot can tell you it's because something DOESN'T go wrong at the cellular level. Hmmm.

As for studying why people don't get cancer, if they think this is a good idea, then perhaps they would also be interested in why people without lungs full of fluid don't drown!

Seriously, we already have "cured" cancer. It's reduced to an acceptable probability vis-a-vis natural selection's point of view. Your immune system does an incredible job of catching cancer many, many times over the course of your lifetime. To respond to paulthebassguy's comment: Sorry, we already have natural cancer resistance that works incredibly well. It's all a matter of statistics. Take a look at how many people actually have cancer, then consider how many DNA base pairing events occur over the course of each person's lifetime. Crunch the numbers and you'll find that we are almost impossibly resistant to cancer.

Ah well, it's the nature of humans to focus on the times things go wrong, rather than the number of times things go perfectly well undetected.
gwargh
2.5 / 5 (4) Jan 23, 2009
You know, we could spend all the effort figuring out a cure for cancer now, or we could just be patient and wait a few thousand years for Darwin to do his thing and give us natural cancer resistance.

Cancer is the result of methods brought about by evolution failing. And there's no one specific cause to why it happens. Think of it this way: the more complicated a machine, the harder it is to fix when it breaks. So further evolution will only complicate this machine. And be sure that the human body is, by all means, a machine, and cancer is a breakdown.
Soylent
5 / 5 (1) Jan 23, 2009
Cancer is the result of methods brought about by evolution failing.


No, most cancers occur far after reproductive age.

It's doubtful that having old people around consuming resources and generally not being of much use other than information storage is worthwhile in a hunter-gatherer society. Evolution might even select FOR cancer.
E_L_Earnhardt
3 / 5 (2) Jan 23, 2009
Coments bear witness. The young don't "give a damn". When you, or your loved ones get it, you may care!
Understanding cell function and malfunction is worth far more than "space travel" or photo cells, or YOU!
freethinking
2.2 / 5 (5) Jan 23, 2009
Death is not normal, nor desirable for any organism. If "evolution" designed death, its terrible. An organism that lives indefintely, will create more copies, than one that doesnt, and so evolution, if its true, should have organism living longer and longer, so they can have more offspring.
bmcghie
not rated yet Jan 23, 2009
freethinking, I think you need some serious justification for that statement. "Death is not normal... for any organism"? Hardly. Every organism dies, I would think that qualifies as normal. If you were to limit your statement to simply "Death is not desirable to any organism" then I would be more inclined to believe you. As it stands, it would seem that for survival of the race as a whole, it becomes less efficient to prolong an individual's survival beyond a certain point. For example in humans, mitochondrial damage is a byproduct (cause?) of aging, and in terms of overall species fitness, it does not make sense to have those kinds of members kicking around.
gopher65
not rated yet Jan 23, 2009
bmcghie: There are some organisms (have to be careful when spelling that word:P) that don't die from aging (ever), such as hydras (the animal, not the mythological creature).

However, you are correct in stating that death-via-ageing is normal.

In order to understand the reason for ageing, you have to ignore complicated things like us, and look at something simple like bacteria, otherwise there are just too many factors to take into account. Bacteria age too, but why? They "age" as damage is slowly accumulated in the cell. Then, when the cell divides into 2, one of the cells takes *all* of the damage, leaving the other cell undamaged ("young"). That now-damaged bacterial cell continues to divide, taking all of the cumulative damage onto itself, until it is too damaged to function, then it dies. It essentially commits suicide in order to keep its offspring from having a detrimental number of genetic mutations.

So ageing is just one particular method of mitigating cell damage, and allowing undamaged, young offspring to continue forward in your place, propagating the species.

There are other methods for doing this (else there wouldn't be non-ageing species around), but clearly ageing must have some evolutionary advantage. Probably something like what Soylent mentioned above. Ageing helps to naturally curb population growth, and it stabilizes specieseseses. So from a certain point of view, it's a good thing.
DickKarpinski
not rated yet Jan 25, 2009
But Dr. Zheng Cui (IIRC) at Wakeforest found cancer resistant mice and people whose neutrophils and macrophages and maybe natural killer cells gang up on cancer cells and kill them. But not for all people or old people or people in the winter or people who have had a great upset in the last few days. He should be starting clinical trials in June or so this year using neutrophil rich centrifuged blood from cancer resistant people to transfuse into cancer victime. Sometimes it's called LIFT for Leucocyte InFusion Therapy, but the clinical trial hasn't begun yet.

And Peter Duesberg, the hero, has shown that cancer is NOT a genetic disease. It's a disease of aneuploidy. Cancers have the wrong numbers of chromosomes or badly broken ones. He even has an aneuploidy test to be used on pap smears which are indeterminant.
superhuman
3 / 5 (2) Jan 25, 2009
Cancer is all about chance. Each our cell has over 3 billion DNA base pairs, and DNA is constantly being damaged and repaired, most damage does not cause any problems but there is a tiny fraction of genes which are required to hold the cell in check and once all of them are damaged the cancer develops.

That said there are still some unknowns, especially important from cancer POV and still not well understood is nuclear structure, but it is actively being explored and hopefully we will know much more shortly.

The article does not make much sense, we do of course look at healthy people, that's how the majority of our knowledge about cancer was obtained - by comparing ill and healthy people.

As for evolution it's goal is not to cure every disease, only to bring them down to manageable levels, evolution is all about *economy*, if the cost of additional resources required to further lower incidence of the disease outweights benefits such outcome is of course not desirable and will be selected against.

Death is required for evolution to work, and evolution actively regulates longevity of every species including humans.
zafouf
4.7 / 5 (3) Jan 25, 2009
A lot of the people who don't get cancer, don't get it because they die of heart disease.
DickKarpinski
not rated yet Jan 27, 2009
superhuman: No, cancer is not a merely genetic disease. There are non-mutagenic carcinogens such as asbestos. Cancer is an occasional result of unstable cell lines due to aneuploidy from any cause. The lengthy series of random reselections of whole chromosomes until one set reproduces faster is why the result may take decades after the insult. Of course, other damage to the repair enzymes like p-53 do make it more likely, eventually. And cigarette smoke likes to damage two particular spots on the P-53 DNA with some biphenyls. We inhale to put it in our lungs.

But Dr. Cui at Wakeforest has discovered many humans with neutrophils and macrophages which seek out and kill any cancer cells not suppressed in other ways. This mechanism fails in winter and even for days after a severe upset. Clinical trials for his Leukocyte InFusion Therapy (LIFT) are expected to start in June.

Malthus guarantees that deaths will occur eventually if fitter survivors who reproduce well consume all the food, but otherwise evolution only requires that fitter offspring reproduce more successfully. But major evolution of big slow animals like us will usually take many thousands of years, not just a few.
googleplex
5 / 5 (1) Jan 27, 2009
Death is required for evolution to work, and evolution actively regulates longevity of every species including humans.

Wrong.

Proof by contradiction is one of the most powerful proofs in mathematics.
Look up Sea Urchin and longevity. This organism does not suffer age related disease. Under ideal conditions they could live for 1000's of years.
Clearly the sea urchin evolved from something else, but it does not have death programmed into itself. This contradicts your hypothesis. Hence your hypothesis is disproven.

Your comment that cancer is "all about chance" is puerile. Look up carcinogen and cancer genotypes.
googleplex
not rated yet Jan 27, 2009
"Today in the world of research funding you need to conform otherwise be ostracized as a crackpot. "

That's always been the case, in every field, not just science. Because, generally people who sound like crackpots, are crackpots.


Amazing. Can you show me Tesla's applications for funding. Also Edison, Brunel, Stephenson, (inventor of the wheel), Da Vinci's, Thomas Crapper. There are an enormous amount of inventions that were not funded.
My point is that the magic of eccentric back yard experimentation has all but disappeared. Research funding is good but it relies on predictability to some extent.
psommerfeld
not rated yet Jan 28, 2009
The only thing I hope is that 15 years from now (and hopefully much sooner), the medical establishment will look back and realize that chemotherapy as a cancer treatment was the greatest medical mistake in modern history. It seems as advanced as using arsenic to treat war wounds, as was once done. The fact that the treatment is often as bad or worse than the disease, its poor success rate, and, probably most importantly, that it has such poor affinity to cancer cells, makes it a Dark Ages treatment. The answer has to be immunological (re)construction and not wholesale cellular destruction.

-- Pete
superhuman
not rated yet Jan 29, 2009
superhuman: No, cancer is not a merely genetic disease. There are non-mutagenic carcinogens such as asbestos. Cancer is an occasional result of unstable cell lines due to aneuploidy from any cause. The lengthy series of random reselections of whole chromosomes until one set reproduces faster is why the result may take decades after the insult. Of course, other damage to the repair enzymes like p-53 do make it more likely, eventually. And cigarette smoke likes to damage two particular spots on the P-53 DNA with some biphenyls. We inhale to put it in our lungs.


I never said "cancer is merely genetic disease".
Cancer happens when the cellular program gets corrupted to the point that failsafe mechanisms which should kill the cell in such a case also fail and the cell goes on a progressively more chaotic dividing spree following it's more and more erratic code.

Aneuploidy results in very extensive damage to cells genetic code, far more extensive than what is enough to cause cancer.

As for the p53 it does not repair damage itself it signals damage and initiates response.

The part about the smoke leading to damage in two specific places in gene's DNA sounds exceedingly improbable to me, small molecules can't specifically target genes as it requires extensive contact surface to differentiate between various base sequences.


Wrong.

Proof by contradiction is one of the most powerful proofs in mathematics.
Look up Sea Urchin and longevity. This organism does not suffer age related disease. Under ideal conditions they could live for 1000's of years.
Clearly the sea urchin evolved from something else, but it does not have death programmed into itself. This contradicts your hypothesis. Hence your hypothesis is disproven.

Age is obviously not the only source of death, you can always get killed!

It's very easy to see why evolution requires death. Imagine we have an organism which never dies, as it procreates it will soon completely fill it's environment and what then? No more evolution. To evolve old organisms need to be removed somehow, unless you assume the environment has unlimited resources which is unrealistic.

Your comment that cancer is "all about chance" is puerile. Look up carcinogen and cancer genotypes.

I know plenty about carcinogens and genetics and I fail to see how it disapproves what I said, so try to be more specific.
googleplex
not rated yet Jan 30, 2009
It's very easy to see why evolution requires death. Imagine we have an organism which never dies, as it procreates it will soon completely fill it's environment and what then? No more evolution. To evolve old organisms need to be removed somehow, unless you assume the environment has unlimited resources which is unrealistic.


Well it looks like you were indeed outwitted by the sea urchin. Are you unable to explain this aparent contradiction with your theory that death is essential to life? Are you making some kind of spiritual/religous point. I am talking from a purely scientific stance.

Why are we not over run with sea urchins even though they don't die of old age. Well the reason is that there are other limiting factors e.g. food scarcety, vulnerability to predation as they grow bigger.
superhuman
not rated yet Jan 31, 2009
Well it looks like you were indeed outwitted by the sea urchin. Are you unable to explain this aparent contradiction with your theory that death is essential to life? Are you making some kind of spiritual/religous point. I am talking from a purely scientific stance.


From scientific stance you need to provide evidence that sea urchins never die. Until then theres nothing to discuss really.
superhuman
not rated yet Jan 31, 2009
One more thing as it seems to me you might be referring to my theory that human aging is the direct product of evolution, in that case you should keep in mind that not all species are in the same situation, the relative importance of aging as a mechanism of removing old individuals depends on the evolutionary setting, if other factors constantly limit the population more then what would be optimal from evolutionary POV then aging might even be non existent. Nothing here contradicts my theory.
superhuman
not rated yet Jan 31, 2009
And one last thing, I tried to look up see urchin as you said and so far I found *estimates* that some individuals can live up to 200 years or more with few signs of aging, with average lifespan being guesstimated at 10-12 days.

This seems to contradict your statements, so can you provide the source for your claims of 1000 years?

http://oregonstat...chin.htm
http://www.stanfo...time.htm
smiffy
not rated yet Feb 01, 2009
Death is required for evolution to work, and evolution actively regulates longevity of every species including humans.
I think that you might have to modify the universality of your theory a bit. Take, for example, a species from the Archaea genera (or indeed any organism which reproduces by binary fission).
In the population of Archaea found today there could exist an organism that has been around for billions of years, and might be around both in principle and in practice for as many more years as the environment continues to support it.
Granted, the chances are that the genotype might well have changed over the aeons, with the original genotype dying out, but I don't see that that is a necessary change. It could easily have stayed the same without having a deleterious effect on evolution, providing support continues from the environment. In the cases of most microbes it's the environment that predominantly determines longetivity, not evolution.
prime
4 / 5 (1) Feb 04, 2009
Cancer is a disease of an embryonic stem cell, Laird, Nature Genetics last year, and Otto Warburg about 80 years ago, and E.V. Gostjeva , Jan 2006 paper on bell shaped nuclei, and as implicated by Robt A Weinberg in his work , switching only 3 genes to start cancer in many human cell types. Telomerase is always involved, as it imparts much of the embryonic nature to a cell, switching 60 genes to growth mode, as well as another 144 genes of unknown effect.
The junk DNA , so called junk DNA determines which genes in the cell are expressed, and this is determined by the poisons we eat, drink, and inhale, as opposed to good clean air, water, and healthy foods.
prime
4 / 5 (1) Feb 04, 2009
So though a smoker, if you are eating the right foods, organic, and so causing the right genes to be expressed, then you might not get sick. Eating right and good air and water are our defense against the corporate poisoners who run our government. And they consider being addicted to tobacco an exercise of free will,, but forbid pot even when its beneficial for a patient with m.s. or other nerve pain.

Then there are the farm poisons in ou water, atrazine (banned in Europe) which converts male hormone to female hormone via aromatase, and several more pesticides which mimic estrogen. Probably causative of breast cancer and other cancers. Then there is BPA in plastics, banned in Europe, but in every bit of plastic your food and drink are stored in. It leaches into your food/drink, and is a great estrogen mimic. It drives cancer past the immune systems ability to react and kill it. Same for the emotional stress that our corporate government wants to keep us under, it demolishes the immune system, (Dr. Elizabeth Blackburn, Lasker Prize for telomerase discovery, in her webcast studying the effect of cronic stress on telomere length in T cells. So, a faulty immune system to oppose initial canccer growth, too many carcinogens, emotional stress that shortens T-cell lifespan and viability, estrogen mimics and converters that boost cancer growth , further eliminating the chance of a good immune response as many cancers contain estrogen receptors which when filled boost growth rates of the tumor.

Otto Warburg: A tumor and a fetus grow at the same rate, and, both rely upon anaerobic glycolysis in order to process enough sugar to energy to support their embryonic programmed rate of growth.
prime
4 / 5 (1) Feb 04, 2009
I like the latest work on Sodium phosphate, the stuff they mix with water and inject into most meat in the U.S., a recent published study says at the dose we receive in the American diet, that it should be activating the AKT lung cancer pathway. It's in most baked goods, cakes and pies, sweets, stuff the kids eat, the doughnuts at the corner shop, and its part of the ammonia nicotine delivery system to boot. The slaughter houses increase the weight of meat by up to 50% by injecting with sodium phosphate solution, FDA justification is that it preserves the meat and prevents germs from growin, but they overinject because every drop of the solution they can inject turns into cold hard cash.
Alexa
1 / 5 (1) Feb 08, 2009
The speed of evolution and mutation must remain always balanced in accordance to life conditions. Prokaryota still rely to horizontal gene transfer, simply because they can divide fast. Sexual reproduction is too mutagenic and energetically expensive for tiny organisms with fast paced live cycle (protozoa), so they using it only in under unfavorable conditions.

Large organisms can reproduce sexually, but sometimes tend to parthenogenesis under good life conditions: for example sharks are living in very stable conditions, so they don't evolve fast, they don't require mutations, so they're cancer resistant and hammerhead shark can reproduce asexually. A endometriosis and/or male associated infertility can be understood as an attempt for evolutionary adaptation of human organism to wealthy life conditions, where the sexual reproduction leads to unnecessary high mutagenity.
Alexa
1 / 5 (2) Feb 08, 2009
today in the world of research funding you need to conform otherwise be ostracized as a crackpot.

Yep, this is the way, how lack of money is working by AWT. Science needs more and more money for basic research of boundary phenomena, so it becomes more and more conformist gradually, because grant system supports only safe ways of research.

But it's not just a result of low money support. Scientific life can be very easy, when you're sufficiently clever and .... conformist. Many scientists have found an easy and comfortable way of existence in grant system of research less or more subconsciously.
superhuman
not rated yet Feb 09, 2009
Death is required for evolution to work, and evolution actively regulates longevity of every species including humans.
I think that you might have to modify the universality of your theory a bit. Take, for example, a species from the Archaea genera (or indeed any organism which reproduces by binary fission).
In the population of Archaea found today there could exist an organism that has been around for billions of years, and might be around both in principle and in practice for as many more years as the environment continues to support it.
Granted, the chances are that the genotype might well have changed over the aeons, with the original genotype dying out, but I don't see that that is a necessary change. It could easily have stayed the same without having a deleterious effect on evolution, providing support continues from the environment. In the cases of most microbes it's the environment that predominantly determines longetivity, not evolution.


Organisms that reproduce by binary fission do not continue forever, mother and daughter cells are not equal, after certain number of divisions mother cells stop dividing and die.

Archea do not live forever I am not sure why do you think they do.
superhuman
not rated yet Feb 09, 2009
Cancer is a disease of an embryonic stem cell


Not really this is an oversimplification, simply stem cells are much easier turned into cancer cells then other types of cells which have additional safeguards build in as they are not dividing forever. There are many cancers which do not originate from embryonic stem cells.

The junk DNA , so called junk DNA determines which genes in the cell are expressed, and this is determined by the poisons we eat, drink, and inhale, as opposed to good clean air, water, and healthy foods.


Multitude of factors determines which genes are turned on or off, yes food and non coding DNA are included but they certainly are not the only factors, the most important are the genes themselves.

So though a smoker, if you are eating the right foods, organic, and so causing the right genes to be expressed, then you might not get sick.


Well yes, but it's not that the "right genes" cure damage done by smoking or something, rather smoking and food poisons are two independent risk factors, eliminate one and your chances to get ill drop.

There is no direct one to one link between what we eat and what genes are expressed, the huge majority of food poisons do their damage by interfering with cellular processes, for example by inactivating proteins, ion channels etc, not by turning on "bad genes."

Besides the whole division of genes into "good genes" and "bad genes," is silly at best, all genes have specific roles more or less beneficial to the cell, but it all depends on circumstances, a gene may be life saver in one circumstances and lead to disease in another even though it's still the same gene in both cases.
tkjtkj
not rated yet Feb 09, 2009
You are asking the wrong question:
rather, you must ask why, of a trillion or more body cells that make up a person, does ONE cell become cancerous. Cancer is far, far more rare, on a cellular basis, than you seem to believe!
smiffy
not rated yet Feb 10, 2009
Organisms that reproduce by binary fission do not continue forever, mother and daughter cells are not equal, after certain number of divisions mother cells stop dividing and die.
Archea do not live forever I am not sure why do you think they do.

Archaea are the best example I can find since they reproduce asexually and do not form spores. That means that the only difference between members of a specific species of Archaea will be that due to chance mutation or some other unusual gene transfer. From Wikipedia - "meiosis does not occur, so if a species of archaea exists in more than one form, these will all have the same genetic material". If the genetic material is identical, and they have no organelles, then any differences must come from the cytoplasm. I just can't see how that can be.

The terms, mother and daughter, are misleading since both progeny are identical - identical twin sisters would be a better term. Because they are identical there can be no way that any of the sister cells can be distinguished in order for it to die after a number of generations. Therefore, providing that the environment is benign enough and the competition is not overwhelming, a specific species of archaea could in theory last for any amount of time. Within that species there will always be one of the original organisms. There is no imperative from evolution for these creatures to die of 'old age'. There's not even any advantage for them to do so.
googleplex
not rated yet Mar 27, 2009
To the guy who said cancer is rare.
Incidence of life time clinical cancer in males is approx 50%, females is sub 40%. Hardly rare by statistical definition.

On the sea urchin. The species shows no discernable signs of aging. Looking at how long it lives in a tank and in the wild is not the key. More research is needed into the cells of these organisms. We effectively no nothing about cell function for any living thing. The cell needs to be precisely mapped at a molecular level and then we can begin to understand its function. There is not even a co-ordinated effort to map the cell collectively and centralize the data. This is in contrast to the co-ordination for the DNA mapping.