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Author Topic: A New Cancer Theory  (Read 26282 times)

Offline iko

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Re: A New Cancer Theory
« Reply #25 on: 22/09/2006 11:58:18 »
Cancer and immunity. Unfortunately it is an overstudied topic that has given poor results in terms of practical applications for the patients' sake in the past few decades.
If you consider immunity even the whole inflammatory process plus local stimuli involved (e.g.: angiogenesis, citokine network and so on), I can understand.
But if we wonder of an overspecialized system watching our body as a sentinel and eliminating every abnormal cell from the start...it could be just fantasy.  The so called "nude mice", selected roditors without thymus and immune defense have to live in a sort of sterile environment not to succumb to infections; they accept and let grow any implanted tumor and this capability has been very important for research.  But they do not develop spontaneous cancers at higher frequency compared to immunocompetent mice.  They only have greater incidence of lymphomas or leukemias, particular tumors originating from their already heavily deranged immune system.
Of course this example is not enough and nothing is so simple.
iko
« Last Edit: 22/09/2006 14:19:48 by iko »
 

Offline ATB

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Re: A New Cancer Theory
« Reply #26 on: 24/09/2006 10:09:40 »
Whilst cancers may have multiple causes (including fungi) in general the cause of cancer appears to be becomming clearer.

The long and short of the current data is;

Cancer is caused by stem cells, for want of better words, that 'have gone wrong'.

The cancer growth appears to be induced by local damage and an upregulated response to grow and synthesise new tissue, which in itself may increase the risk of certain pro-tumour mutations during the cellular stress experienced by these cells.

As the process progresses, stem cells actually react to the circumstance more locally and derrive a survivalistic mode that encourages them to break away from normnal cell-to-cell signalling, and hence growth down-regulation.

Once freed, the cells basic perogative is to adapt to the local mal-nutritive circumstances by triggering increased blood vessel growth to supply it in its starvation state and to migrate to other locations where it can derricve nutrients.

The cells actually evolve changes to survive under a progressive malnutrition, and the migration and invasion of malignant invasive cancers is the ultimate expression of this form.

As the cancer grows, it increases nutrient loss and impairs the ability of the cells to be directed by normal tissues which would try to force them to specialise into useful cells with limited reproduction.

The cells start to adapt to the circumstances, which they are able to do, due to the fact that they are multi-potent stem cells that can effect local changes in adaptation and form, and migrate as stem cells can. This explains all the major forms of cancer.

the cancer evolves to survive and obtain nutrients, though this is a normal but usually highly regulated stage of stem cell replication and migration, but in the cancer, becomes continuously expressed and unregulated.

A very interesting type of cancer has been found recently in dogs -  a transmissible cancer that evolved from an ancestral dog and is therefore a kind of odd dog parasite, based on dog DNA.

The only known example of an animal evolving a transmissable parasite of itself, I believe.


« Last Edit: 24/09/2006 10:12:01 by ATB »
 

Offline iko

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Re: A New Cancer Theory
« Reply #27 on: 24/09/2006 10:31:03 »
Ok Alan,
As I tried to make clear before, we ought not to generalize too much around here.
Quoting stem cells (everybody does it these days) and fungi here and there is not exactly a theory.  I mentioned a specific example of cancer that supported the infectious theory and could be extended to other types ot tumors.  I had to cite 2 names and a specific bug (Helicobacter pylori) to allow anybody to search through literature and rule out that's not just my imagination.
It is a serious matter with a lot of human suffering involved.
I assume that a good theory -when confirmed- leads to practical results...it's not philosophy at all.

Quote
...
A very interesting type of cancer has been found recently in dogs - a transmissible cancer that evolved from an ancestral dog and is therefore a kind of odd dog parasite, based on dog DNA.

Why don't you try to explain shortly and clearly this interesting thing?
iko

P.S.  You sound quite smart for a 13 years old boy!

iko
« Last Edit: 05/03/2008 22:37:58 by iko »
 

Offline ATB

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Re: A New Cancer Theory
« Reply #28 on: 24/09/2006 10:41:24 »
Oh, thats a mistake, I clicked my age right when I joined but it comes up 13 - I am 29!
 

Offline Gaia

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Re: A New Cancer Theory
« Reply #29 on: 24/09/2006 11:04:34 »
quote:
Originally posted by ATB


A very interesting type of cancer has been found recently in dogs -  a transmissible cancer that evolved from an ancestral dog and is therefore a kind of odd dog parasite, based on dog DNA.

The only known example of an animal evolving a transmissable parasite of itself, I believe.



From Chemistry & Industry 21 Aug 2006, Issue No 16, Pg 5, News    

SCIENCE BRIEF
Contagious dog cancer

A contagious form of dog cancer is spread by transmission of the cancer cells themselves, according to researchers in the UK and US.

Using forensic DNA analysis, researchers examined canine transmissible venereal tumour (CTVT) and blood samples from 16 unrelated dogs in Italy, India and Kenya, and tumour samples taken from 40 dogs in five continents. They found that DNA from the tumours did not match blood samples, showing that the tumour cells didn’t belong to the dogs. But the tumours from all over the world were closely related to one another. By comparing the sequences of the tumour genes with related genes of grey wolves and dogs, they traced the origin of CTVT to wolves or a closely related dog breed that lived over two centuries ago.

‘The cancer escaped its original body and became a parasite transmitted from dog to bitch and bitch to dog until it had colonised all over the world,’ said one of the researchers Robin Weiss, of University College London.

The researchers say CTVT is transmitted through sexual contact and other activities such as licking and biting tumour-affected areas. And the findings, they said, could raise important new ideas about the instability of cancer as CTVT shows no evidence of progressive instability.

A similar phenomenon could be possible in immunocompromised humans, the researchers suggest.

Gaia  xxx
 

Offline iko

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Re: A New Cancer Theory
« Reply #30 on: 24/09/2006 14:21:32 »
quote:
Originally posted by another_someone
So you are saying that all the effort people are putting into trialling a vaccine against Human Papilloma Virus to protect against cervical cancer is all a waste of time and money?
George


Human Papilloma virus HPV 26 seems to do the same in humans, causing cervical cancer.

iko
« Last Edit: 24/09/2006 14:23:48 by iko »
 

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Re: A New Cancer Theory
« Reply #30 on: 24/09/2006 14:21:32 »

 

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