[thedoc (OP)]

Paul Anderson  asked the Naked Scientists:
   Is it known yet why apoptosis does not apply to cancer cells, or is that the big question that everyone is still trying to answer?

Is it possible to pump gene p53 into areas affected by cancer or directly into a tumour and would that be effective? Has that already been tried?

Regards
Paul
NZ
What do you think?

[evan_au]

There is a chain of events that leads to apoptosis (cell suicide); a break in any one of these steps means that apoptosis will not occur. The actions of P53 is certainly an important one of those steps.

Some recent research investigated the paradox of how large animals like elephants don't all die of cancer at a young age. It was found that they have multiple copies of P53 in their genome, so presumably it would take multiple mutations to disable all of these copies.

There are a variety of cellular mechanisms that prevent a cancer from running amok. One of these is telomere shortening, which stops cells from dividing a large number of times. But a mutation that turns on telomerase will allow a pre-cancerous cell to become immortal.

And so it takes a number of mutations to cause a cancer to form. Gene sequencing is sometimes used today to determine which particular mutations are present in a cancer, and to determine if there are any medications known to attack this mutation.

Once a cell has become cancerous, its genome becomes unstable, and it undergoes a fast rate of evolution. This means that a cancer often returns (sometimes years later), in a form resistant to the previously-successful treatment.