This is no surprise to those involved in cancer research. Keep in mind that every cancer can be thought of a different disease. This is true of any cancer you can think of, whether that's brain, intestine, liver, kidney, bladder, skin, etc etc etc etc... Even in those organs there are multiple types of cancers, each with its own genetic profile. Then even in one type of cancer, there's always a complex interplay of genes. We seem to think that one specific gene is required for malignant transformations, but that's only a model. It's very rare (ever?) that a gene is transformed in a common type of cancer 100% of the time. Then even if you target that gene or its products you may still not actually kill the cancer. This has been seen over and over again. Our bodies are crafty, even when they go awry!
This all means that one "magic bullet" for cancer is unlikely. The goal there would be not to attack a specific gene of cancer, but a process. Cancers proliferate quickly, so most chemotherapy targets proliferation. There have been attempts to target the blood supplies of cancers, but to little avail. But people get looking... Some labs work on ways to keep it from invading other tissues. But there's all kinds of ideas, and they take many years to go from bench to animal to human.
So the goal of gene therapy has always been for a specific cancer or even subtype of cancer (Gleevec is the prototype pharmacologic example of this), not all of them at once. Unfortunately, gene therapy comes with its own side-effects and issues of specificity, and so it's always been a challenge.
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09-07-2008, 02:07 AM
