Explain why protecting surviving rainforests from deforestation is important to fighting cancer.

Some 120 prescription drugs sold worldwide today are derived directly from rainforest plants. And according to the U.S. National Cancer Institute, more than two-thirds of all medicines found to have cancer-fighting properties come from rainforest plants. Examples abound. Ingredients obtained and synthesized from a now-extinct periwinkle plant found only in Madagascar (until deforestation wiped it out) have increased the chances of survival for children with leukemia from 20 percent to 80 percent.