Doctors have treated only three leukemia patients, but the sensational results from a single shot could be one of the most significant advances in cancer research in decades. Doctors at the University of Pennsylvania say the treatment made the most common type of leukemia completely disappear in two of the patients and reduced it by 70 percent in the third. In each of the patients as much as five pounds of cancerous tissue completely melted away in a few weeks, and a year later it is still gone. The results of the preliminary test exceeded our wildest expectations," says immunologist Dr. Carl June a member of the Abramson Cancer Center's research team. Chemotherapy and radiation can hold this form of leukemia at bay for years, but until now the only cure has been a bone marrow transplant. A bone marrow transplant requires a suitable match, works only about half the time, and often brings on severe, life-threatening side effects such as pain and infection. So why has this remarkable treatment been tried so far on only three patients? Both the National Cancer Institute and several pharmaceutical companies declined to pay for the research. Neither applicants nor funders discuss the reasons an application is turned down.