Summarize the cellular effects of cancer.

[Drayakir]

Hullo. I was supposed to briefly summarize the cellular effects of cancer. I was wondering if I should add anything to this:

"Cancer on the cellular level is really quite simple. What happens, is that the cancer mutation forces cells to rapidly accelerate all steps of their cycle. The greatest increase is for the interphase, during which the protein synthesis for cell reproduction, and DNA replication take place. The four cells of mitosis also accelerate, causing an abnormally fast cell-division process.
This is the lethality of cancer. Cancer does not give cells enough time to split the organelles evenly, and even if it does, they are rendered inactive. Not only do the cancerous cells stop working, they also infect cells around them, causing those cells to be rendered inoperative as well."

Any feedback would be greatly appreciated. Thanks.

 

[Jikx]

What happens, is that the cancer mutation forces cells to rapidly accelerate all steps of their cycle. The greatest increase is for the interphase, during which the protein synthesis for cell reproduction, and DNA replication take place. The four cells of mitosis also accelerate, causing an abnormally fast cell-division process.

I don't think its an absolute necessary attribute of all cancers to have accelerated growth (beneign tumours come to mind). I was under the impression that cancer cells ignore environmental cues that would normally cause it to stop dividing (eg contact inhibition) at the various "checkpoints" of the cell cycle, and also not require the presence of growth factors to divide. But accelerated growth is a feature of most cancer cells.. i think.

Cancer does not give cells enough time to split the organelles evenly, and even if it does, they are rendered inactive. Not only do the cancerous cells stop working, they also infect cells around them, causing those cells to be rendered inoperative as well

Cancer does not infect or transmit itself.. a visible tumour is essentially derived from a single cancerous cell. There are instances of viruses (SV40?) that can cause cancer however due to the insertion of oncogenes which bypass the "checkpoints".

I'm not sure either that cancer cells become inactive either.. all I've seen in the lab is that they just keep growing until they exhaust the nutrient supply, in which case the cells start to die. Although some do seem to die before that point, I haven't heard that to be due to uneven distribution of organelles either.. but I have heard about funky chromosomal abnormailities (because the "is chromosome separated/replicated properly" checkpoint is bypassed) that could be possibly be the cause of this.

But in vivo, i think cancer kill by blocking ducts (food, air), pinching nerves, cutting off blood, forming clots, depriving nutrients to normal cells etc.

 

[Monique]

Jikx is right, cancer cells don't have an accelerated cell cycle: they have an uncontrolled cell cycle. A cancerous cells is effectively autonomous: it provides it's own growth factors and doesn't listen to growth-inhibitory signals from neighbouring cells.

Approximately 50% of all tumours have a mutation in the gene p53, it is thought that approximately 90% of all tumours have a mutation in the p53 pathway. The p53 pathway is involved in DNA checkpoints, when it is mutated it can't signal a cell to stop dividing.

Essentially what happens is that during replication, errors occur which don't get repaired. Also, since cancer cells replicate very rapidly their chromosomal tips begin to damage (the telomeres, even with the expression of telomerase): the tips become sticky and chromosomes start to stick to each other. During segragation the chromosomes will be torn apart, resulting in strand breaks. This is where the chromosomal translocations happen.

So, if you want to describe a cancerous cell.. I'd say it's an autonomous cell that supplies itself with growth factors and doesn't listen to other cells, and that it has the ability to divide forever (with the expression of telomerase).

 

[Drayakir]

THanks for the help. I really appreciate it, seeing that is due today.

 

[ph]

heard it in a SP song

to have cancer, one has to say "yes" to it at some level. that's all i know.

(!xck)