4 out of 10 patients now diagnosed with cancer will still be alive in five years. But the majority may not survive that long unless the promising new treatments now slated for testing prove victorious. Right now, Corey and Janet maintain normal lives. The disease-fighting immune system is programmed to destroy abnormal cells, like cancer cells. Scientists now know normal cells begin to split and produce copies of themselves through a complicated process.
Cells produce substances called growth factors.
These substances bind to receptors on the surface of cells, like keys fitting into locks. Growth factors trigger cell division. Cancer cells flaunt the rules. Hundreds of thousands of cancer cells combine to form a tumor. Once the tumor grows big enough, bits of it can break off and spread through the bloodstream to other body parts.