Does Virtually Everyone "Get" Cancer?

[imp]

Given one of the body's organs, let's say the pancreas, cells making up the organ are continually being replaced as present cells age and die. For some reason one division of cells produces new ones which differ in their reproductive process; they reproduce too soon. Those new cells, reproducing too quickly, constitute a "pancreatic cancer"

 

Assuming the above happens, and that it happens frequently, do you believe the normal body is quickly aware of the abnormal cells, and makes every effort to eliminate them?

 

If so, it follows that should the body be unable to totally eliminate those relatively few new abnormally multiplying cells, the pancreas has become "cancerous".

 

Is the above process plausible? It would explain several of the mysteries of cancer. imp

[Wormwood]

Hi Imp

 

First, your explaination for the genesis of cancer is incomplete. When some cells divide, there is an abnormality that causes a lack of differentiation in cells after division. This is what causes the defective cancer cells, and the rapid multiplication. Normally, cells start out as spore cells, or stem cells, then they become differentiated to become specific cells (like skin cells, muscle cells, pancreas cells, etc) But when someone gets cancer, their cells lose differentiation due to genetic damage and the mechanisms that regulate normal cells are disabled. That is why cancer replicates really fast and why most cancer cells are immortal.

 

Yes the body has mechnisms that detect and destroy damaged cells usually. As we get older, or our systemic health is compromised, the number of mutations outnumbers the capacity of the body to destroy them and cancer develops. Usually cancer is from one cell or region and then it spread to other regions through the bloodstream. This is why you could have pancreatic cancer in your leg.

 

I hope this helps.

[immortal]

If the cells are damaged then the cells are self destructed but in cancerous cells the immune system is not efficient the protective genes will be damaged and can not trigger apoptosis. There are ways to increase the immune response in cancerous cells.

 

Environmental factors play a major role on persons affected by cancer. So virtually everyone does not get cancer.

[Revenged]

~1 in 3 people in the UK dies from cancer... so yes vertually everyone does get cancer but incidence increases with old age as you need multiple genetic defects in a cell to cause a maglignant cancerous cell... this is because the body has numerous controls on cell cycle activity...

 

The best treatment for cancer is still surgery... Chemotherapy is quite cheap but it is often non-specific and simply targets all proliferating cells and so the toxicity is fairly high... The breakthrough chemotherapy drugs are monoclonal antibody treatments as these are partially selective for cancerous cells so the toxicity is a lot lower... but the national health service is refusing to pay for a lot of them as they are too expensive... As you can see, the difficulty with treating cancerous cells is they are often almost identical to normal cells...

[lucaspa]

Given one of the body's organs, let's say the pancreas, cells making up the organ are continually being replaced as present cells age and die. For some reason one division of cells produces new ones which differ in their reproductive process; they reproduce too soon. Those new cells, reproducing too quickly, constitute a "pancreatic cancer"

 

Assuming the above happens, and that it happens frequently, do you believe the normal body is quickly aware of the abnormal cells, and makes every effort to eliminate them?

 

The data says this is true. Nearly all abnormal cells either 1) die by apoptosis or 2) are killed by natural killer cells of the immune system. Cancers arise from the, very, rare cell that has changes that abort apoptosis AND keep it from being killed by the immune system.

 

All you need do is do a PubMed search on "immunity, cancer" and "apoptosis, cancer" to see the huge literature documenting what I've said. It's not a matter of "belief", but of knowing what the data is.

 

Current thinking is trending toward the idea that cancer cells are adult stem cells that have lost growth control. Stem cells already have an unlimited ability to proliferate. Their proliferation instead is stopped. Block that "turn off proliferation" control and you already have both characteristics of cancer cells: they are undifferentiated and have no growth control. Then "all" the cell needs is a way to keep the immune system from killing it.

[lucaspa]

~1 in 3 people in the UK dies from cancer... so yes vertually everyone does get cancer but incidence increases with old age as you need multiple genetic defects in a cell to cause a maglignant cancerous cell... this is because the body has numerous controls on cell cycle activity...

 

No, not "everyone" gets cancer. As you noted, even if we include people who got cancer but were cured surgically, still over 1/2 of people die without every having cancer.

 

However, as age increases the odds that a cell will have genetic defects that give it both the ability to avoid apoptosis AND be able to avoid being killed by the immune system increases.

[lucaspa]

If the cells are damaged then the cells are self destructed but in cancerous cells the immune system is not efficient the protective genes will be damaged and can not trigger apoptosis. There are ways to increase the immune response in cancerous cells.

 

Apoptosis and susceptibility to the immune system are two different but related things. The similiarity is that both the ability to avoid apoptosis and susceptibility to the immune system are due to abnormal proteins. Cells are constantly processing parts of their proteins and putting parts of them out on the cell's membrane for the immune system to "see". A cancer cell has abnormal proteins, therefore the immune system recognizes it as "not self" and kills it.

 

The new treatment does not "increase the immune response in cancerous cells" but instead increases the body's immune response to the abnormal proteins produced by cancerous cells. Some of cancer cells are removed from the patient the complexes on the surface of the cancer cells that react with immune cells are then used to "train" the patient's immune cells -- again outside the body. The immune cells are then put back into the patient and go after the cancer cells. Or sometimes the patient's cancer cells are used to train immune cells to make antibodies to the cancer cells, and then the antibodies are injected into the patient.

[Dhondy]

The OP is close to the truth. We do often get near cancerous cells during repair of tissues. The body has mechanisms to recognize and cause self destruction of such cells, through apoptosis (programmed cell death).

 

At other times, the body's defence system, comprising NK cells, T cells in conjunction with antigen presenting cells, B cells (which produce antibodies), and macrophages recognize the altered cells and kill them.

 

Under certain condition, the apoptotic process fails, as does the surveillence mechanism, and cancer may eventuate.

 

Edit: Somebody got there before me, I see!

[imp]

as I confess to be, what is meant by "OP"? Thank you for accepting my incompetence! imp

[Sepiraph]

as I confess to be, what is meant by "OP"? Thank you for accepting my incompetence! imp

 

I believe it is generally meant to refer to the "original post" or "original poster", depending on the context being used.

[Genecks]

No, not "everyone" gets cancer. As you noted, even if we include people who got cancer but were cured surgically, still over 1/2 of people die without every having cancer.

 

However, as age increases the odds that a cell will have genetic defects that give it both the ability to avoid apoptosis AND be able to avoid being killed by the immune system increases.

 

Ditto. It's about statistics, probability, and time. I'm sure if you could remain "immortal," but you had cells regenerate overtime, then you would face a very high chance of obtaining cancer. So, immortality isn't all it's cut out to be.

[Revenged]

Ditto. It's about statistics

 

And I actually got the statistic wrong...

 

It's 1 in ~3 get cancer... 1 in ~4 die from cancer... and i agree that no 1 in 3 isn't 'everyone' but it is quite a lot...

[lucaspa]

And I actually got the statistic wrong...

 

It's 1 in ~3 get cancer... 1 in ~4 die from cancer... and i agree that no 1 in 3 isn't 'everyone' but it is quite a lot...

 

Yes, it is "quite a lot". But it's even a long way from a majority. The cancer rate didn't use to be this high, because life expectancy was 35-40 and most cancers develop after then. Same with heart disease -- it develops after age 50 and most people died before then. It's only with advances in public health, better nutrition, and antisepsis that we have gotten past the usual killers and are now living long enough to get these diseases.

 

As the main killers were beaten, we (as a society) have come to expect our loved ones (and ourselves) to live a long time. Thus, any process that kills 1 out of 3 is going to be looked at as a "disaster" -- analogous to the disaster of the Black Death, which had about the same kill ratio in the Middle Ages. However, I would submit that, since this a science forum, that we try to stay objective, keep our emotions in check, and not overstate the issue.

 

Notice that evolution is NOT going to have provided adaptations to minimize these diseases. They occur after the childbearing years, so adaptations only have to work to get the individual to live long enough to have kids. After that, natural selection doesn't care and can't "see" the problem.

[armygas]

Environmental factors play a major role on persons affected by cancer. So virtually everyone does not get cancer.

 

I would argue that if you live long enough, most (if not all) people will get some form of cancer. In men, prostate cancer is a prime example, if you live past 80 you should expect to have to be treated for it as you PSA levels rise.

[immortal]

I would argue that if you live long enough, most (if not all) people will get some form of cancer. In men, prostate cancer is a prime example, if you live past 80 you should expect to have to be treated for it as you PSA levels rise.

 

Yes prostate cancer arises when you are more than 50 years old. Cancer arises when you have mutations in the genes so only those people who have mutation in their genes will get cancer not everyone.

 

 

Sorry I could'nt provide the link.

 

"The mutation is just a single nucleotide substitution in the genetic code for this protein, which results in the amino acid alanine being replaced with threonine, but this is enough to change the protein's structure, so that it becomes more efficient, making the prostate grow faster. This does not explain how the mutation causes cancer, but it explains part of the why. The rest of the cause is likely to be an interaction with other mutations caused by environmental factors, somatic mutations, which turn potential into reality. This theory, of course, fits in well with the observations of apparent racial and cultural differences in cancer frequencies."

[armygas]

Yes prostate cancer arises when you are more than 50 years old. Cancer arises when you have mutations in the genes so only those people who have mutation in their genes will get cancer not everyone.

 

 

Sorry I could'nt provide the link.

 

"The mutation is just a single nucleotide substitution in the genetic code for this protein, which results in the amino acid alanine being replaced with threonine, but this is enough to change the protein's structure, so that it becomes more efficient, making the prostate grow faster. This does not explain how the mutation causes cancer, but it explains part of the why. The rest of the cause is likely to be an interaction with other mutations caused by environmental factors, somatic mutations, which turn potential into reality. This theory, of course, fits in well with the observations of apparent racial and cultural differences in cancer frequencies."

 

DNA proofreading is not perfect thus an individual can have a self mutation throughout his/her lifespan so it one doesn't need to be born with the mutation to acquire it later in life, and the more a cell replicates the more chance of a self mutation which is not corrected by intrinsic DNA proofreading mechanisms.

[immortal]

DNA proofreading is not perfect thus an individual can have a self mutation throughout his/her lifespan so it one doesn't need to be born with the mutation to acquire it later in life, and the more a cell replicates the more chance of a self mutation which is not corrected by intrinsic DNA proofreading mechanisms.

 

Yes I agree with that but one more thing you have to remember is you need a number of mutations to make normal cells cancerous and we have people who have lived past 80 years normally. This is more about statistics and the number of people affected by cancer are very less when compared to population of the world (but yes the chances are very high).

 

I need to stress this .

"The rest of the cause is likely to be an interaction with other mutations caused by environmental factors, somatic mutations, which turn potential into reality. This theory, of course, fits in well with the observations of apparent racial and cultural differences in cancer frequencies."

[lucaspa]

Yes prostate cancer arises when you are more than 50 years old. Cancer arises when you have mutations in the genes so only those people who have mutation in their genes will get cancer not everyone.

 

Not quite. Everyone gets mutations, but getting cancer is also a function of several other processes for the mutated cell:

1. It does not undergo apoptosis.

2. It avoids being killed by NK cells of the immune system.

3. The mutations provide uncontrolled mitosis

4. It finds a way to promote angiogenesis.

5. The cells find a way to invade other tissues.

 

Unless the mutated cell does ALL of these, it won't be cancer.

 

So not everyone will get cancer, because not everyone will have cells that are able to do all of these.

[lucaspa]

DNA proofreading is not perfect thus an individual can have a self mutation throughout his/her lifespan so it one doesn't need to be born with the mutation to acquire it later in life, and the more a cell replicates the more chance of a self mutation which is not corrected by intrinsic DNA proofreading mechanisms.

 

Yes, BUT that doesn't mean cancer. Cancer is a DISEASE, not just "mutation". Looking at my previous post, in order to be a disease, the mutation(s) have to give the cell the ability to do all the activities in the list. That is very unlikely, which is why cancers are usually more prevalent later in life: more chances. However, it is not inevitable that mutation(s) will arise giving the cell ALL those abilities.

 

All of us generate abnormal somatic cells thruout life. But they don't become cancer because they are killed, either by apoptosis or the immune system, before they can replicate and acquire the other attributes to be cancer.

[armygas]

Yes, BUT that doesn't mean cancer. Cancer is a DISEASE, not just "mutation". Looking at my previous post, in order to be a disease, the mutation(s) have to give the cell the ability to do all the activities in the list. That is very unlikely, which is why cancers are usually more prevalent later in life: more chances. However, it is not inevitable that mutation(s) will arise giving the cell ALL those abilities.

 

All of us generate abnormal somatic cells thruout life. But they don't become cancer because they are killed, either by apoptosis or the immune system, before they can replicate and acquire the other attributes to be cancer.

 

Uhhh, I was responding to the point that suggested people got cancer "only" b/c they inherited a "mutated" gene, which is clearly not true......

[immortal]

Uhhh, I was responding to the point that suggested people got cancer "only" b/c they inherited a "mutated" gene, which is clearly not true......

 

I apologise for not making it clear but I did'nt say that you need to have an inherited mutated gene for cancer. . What I was trying to say is you need to have a number of mutations for cancer to occur and only those people who have a large number of mutations will get cancer.

 

Remember colon cancer is an inherited disease.

[lucaspa]

Uhhh, I was responding to the point that suggested people got cancer "only" b/c they inherited a "mutated" gene, which is clearly not true......

 

And I was responding to this statment of yours: "the more a cell replicates the more chance of a self mutation which is not corrected by intrinsic DNA proofreading mechanisms." Your response was another misstatement.

 

Just having a mutation does not automatically mean "cancer". Which is what my post was about.

[lucaspa]

What I was trying to say is you need to have a number of mutations for cancer to occur and only those people who have a large number of mutations will get cancer.

 

Not the people, CELLS within the people. A CELL has to have a large number of mutations to be a cancer cell.

 

Remember colon cancer is an inherited disease.

 

No, it's not. You don't inherit colon cancer from your parents. What you inherent are alleles that make it easier for a cell to become cancerous. Not everyone with a parent with colon cancer gets it.