Stem cells — popularly known as a source of biological rejuvenation — may play harmful roles in the body, specifically in the growth and spread of cancer. Amongst the wildly dividing cells of a tumor, scientists have located cancer stem cells. Physician-scientists from Weill Cornell Medical College are studying these cells with hopes of combating malignant cancers in the brain. “Some patients’ brain tumors respond to chemotherapy and some don’t,” says Dr. John A. [click link for full article]