Right now, most cancer treatments are based on the fact that cancers grow very quickly and most of the rest of our cells don't. In fact, most of our cells grow hardly at all once we're adults.
So what cancer drugs do is kill any growing cells. Different cancers respond better to different general killers, but by and large most of these different medicines just clobber growing cells.
Of course you kill the other growing cells in your body too. Which is why these treatments cause hair to fall out, nausea, anemia, etc. The hair follicles, lining of the digestive tract and red blood cells are all bludgeoned by the treatment as well.
And the treatment doesn't even work with some slow growing cancers like prostate cancer. So doctors would like to have more subtle medicines that really target just the cancer cell.
These drugs would work by targeting specific broken genes found in the cancer. Remember, cancer happens when our DNA is changed or mutated.
Cancers are usually classified by what tissue they started out asbreast, prostate, lung, etc. But within these classes there are different subtypes. These subtypes arise because cells become cancerous due to different DNA changes.
Change X leads to a breast cancer that can be treated one way, change Y leads to a breast cancer that can be treated another way. What the Cancer Genome Atlas Project hopes to do is to find different ways to treat all of these subtypes.
We already have an example of a drug like this for breast cancerHerceptin. Herceptin targets cells in which a specific gene, her2, has been turned on. Herceptin kills only the cells that make her2, the cancer cells. This means Herceptin eliminates the cancer more effectively with fewer side effects.
But not all breast cancers make her2. What this means is that Herceptin doesn't work on the other cancers, only the cancers that make her2.
What the Cancer Genome Atlas is designed to do is to find more genes like her2. The hope is that drugs can then be developed that target these genes so that only the cancers and not the other cells will be eliminated. This should lead to fewer side effects as well.