Why don't we get cancer all the time?

[Hercules Rockefeller]

Losing the ability to reproduce was part of the evolutionary path single-celled organisms had to take to become multicellular...

If I understand what you’re getting at then this isn’t a surprising notion, is it? In large multicellular animals, such as humans, only a small percentage of the total cells are proliferative. Tissue turnover is driven by a relatively small number of stem cells and transit amplifying cells that are derived from stem cell division. As it is we can suffer from cancer if a cell escapes the tight controls on its division. Can you imagine the level on control that would be necessary if all of our cells remained proliferative? I can’t imagine that this would be possible.

I was hoping someone would think of the pRb or Retinoblastoma protein or some such.

Regulation of the cell cycle is a very complex subject. For the purposes of this sub-forum and the general knowledge level, I would think that discussion of the specific proteins involved in cell cycle regulation, such as Rb, cyclins, CDKs etc, would be too technical and too much detail.

 

[lucifers angel]

In human cells, both normal metabolic activities and environmental factors such as UV light can cause DNA damage, resulting in as many as 1 million individual molecular lesions per cell per day

A cell that has accumulated a large amount of DNA damage, or one that no longer effectively repairs damage incurred to its DNA, can enter one of three possible states:

1. an irreversible state of dormancy, known as senescence
2. cell suicide, also known as apoptosis or programmed cell death
3. unregulated cell division, which can lead to the formation of a tumor that is cancerous


So why don't we get cancer all the time?

John W. Pepper of The University of Arizona in Tucson and his colleagues used a kind of computer model called an agent-based model to compare different modes of cellular reproduction.

The results indicate that if cells reproduce by simply making carbon-copies of themselves, the cells' descendants are more likely to accumulate mutations.

In contrast, if cellular reproduction was much more complicated, the cells' descendants had fewer mutations.

Multicellular organisms use a seemingly inefficient process to replace lost cells.

An organ such as the skin calls upon skin-specific stem cells to produce intermediate cells that in turn produce skin cells.

Although great at their job, the new skin cells are evolutionary dead ends. The cells cannot reproduce.

Losing the ability to reproduce was part of the evolutionary path single-celled organisms had to take to become multicellular...

i dont know the answer but i would take a guess at it,

if you have cancer in your family you are at more risk, and if your lifestyle is such that you could risk cancer yourself, I smoked for years, and then i gave it up, and my Dr said i may ahve got my cancer from my smoking years.

 

[Roman]

Isn't it also postulated that the lack of telomerase in many somatic cells is another way to keep cells from becoming cancerous? A potentially tumorigenic growth suddenly ceases since the telomerase is inactivate, and telomere loss leads to senescence.

 

[alanejackson]

Here's a quote from a book I recently read; "June 15, 2045 - World Government is officially installed in Sydney Australia. Boris Malinkov, a Russian, begins his first term as the first World President, having received 54 percent of the popular vote and 56 percent of electoral votes in the runoff election against South African candidate Gordon Mondeto. China, formally the most powerful nation on earth, is now the world's most powerful state. On the basis of its smaller population, however, the United States drops from second to seventh. But with complete worldwide freedom of information, political power no longer holds the significance it once did." The Truth Machine, by James L. Halperman

Here's another quote from the same book; "Aging's mostly a result of cell division. Cell division shortens all the chromosome tips, which are called telomeres. After about 60 divisions, the telomeres fall below critical length and the cells die."

The concept of telomeres has recently been put forth by some medical researchers. If true, wouldn't it show its effects during cloning?


How will you react when it is pointed out that cancer is good? It's simply the body's effort to adapt. And overtime, in the big picture, it's the method by which our bodies acquired organs and other structures.

I know, like smoking, our educational system teaches cancer is a plague afflicting mankind. Which implies, if you attack and kill the cancer, and the smokers, everything will be all right. But the reality of the situation is mankind left the environment of the rainforest and now has to compensate for the atmosphere by smoking. And historically this has been viewed as help from God, for thousands of years. And when stem cells mutate in an effort to help man adapt to his lack of movement as he ages, those so-called educated professionals try to teach us it's caused by smokers or something other than ourselves not being right with God.

 

[alanejackson]

Gold Fusion - A 20 Minute Cancer Cure!?!?

Sitting, listening to the science program "Quirks and Quarks", I heard the recipe. Take very small, Nano sized glass balls, cover them with gold, inject them into the tumor and then expose the area to ultraviolet light. Just that simple. The glass balls heat up due to the ultraviolet light. This being detrimental to the cells in the immediate vicinity, while other tissues are unharmed. The woman can even attach these Nano Glass Balls to your cultured macrophages and return them into your body, and after waiting a short time for these reintroduced macrophages to find their targets, apply the ultraviolet light and destroy multiple, perhaps all tumors. I heard she's doing pretty good with mice.

While discussing the recent death of a cancer victim who had had parts of his digestive tract removed, the statement was made: Some say he waited too long before getting treatment. I'm thinking they're the same people supporting the move to occupy Iraq. And evidence they're not aware of indicates they didn't wait long enough.

 

[Hercules Rockefeller]

Here's another quote from the same book; "Aging's mostly a result of cell division.

No, that is not an accurate statement. The aging process in mammals is a very complex phenomenon. There are a variety of theories as to the causes of aging with continual debate as to the relative weighting of aspect of the overall aging phenotype. These include the accumulation of mitochondrial mutations, accumulation of nuclear mutations, oxidative damage to cells/proteins, and the genetic aging 'program' that is specific to each organism. Aging in general is likely to be a result of all the various areas.

Cell division shortens all the chromosome tips, which are called telomeres. After about 60 divisions, the telomeres fall below critical length and the cells die."

Correct, but this is not the sole cause of aging.

The concept of telomeres has recently been put forth by some medical researchers.

Recently? Some medical researchers?

It’s this sort of vague and inaccurate statement that is indicative of a poor understanding of the subject at hand. This field is well over 15 years old, is well-established and is studied by many scientists world-wide, not just some scientists.

If true, wouldn't it show its effects during cloning?

It does. Telomere length in cloned cells is sometimes “reset” and sometimes isn’t – it depends on the organism and the specifics of the nuclear transfer process.

How will you react when it is pointed out that cancer is good?

I would take the opportunity to point out that you are a crackpot complete with ill-conceived looney hypotheses.

It's simply the body's effort to adapt. And overtime, in the big picture, it's the method by which our bodies acquired organs and other structures.

Nonsense.

But the reality of the situation is mankind left the environment of the rainforest and now has to compensate for the atmosphere by smoking.

More nonsense.

And when stem cells mutate in an effort to help man adapt to his lack of movement as he ages, those so-called educated professionals try to teach us it's caused by smokers or something other than ourselves not being right with God.

Ahhh, and you’ve saved the best nonsense till last. And I see you’ve even thrown in the classic crackpot platforms for us:

(i) a reference to some sort of imagined scientific orthodoxy that tries to perpetuate lies and suppress “the truth”, and

(ii) an attempt to introduce concepts of God into scientific discussions.