Researchers who took part in the study used a patient's cloned T cells (helper cells) to put an advanced cancer into complete remission. Nine patients took part in the experimental melanoma treatment program.

The researchers were very surprised after they treated a 52-year-old man from Oregon of his Stage 4 melanoma. The research team led by Cassian Yee, M.D., an associate member of the Clinical Research Division at the Center, took CD4+T cells (white blood cells) from the patient’s body and during the next three months it grew approximately 5 billion of the cells in the lab. Then the cells grown in the lab were injected back into the patient.

After just two months, PET and CT scans revealed no sign of tumors anywhere in the patient's body and there were no harmful side effects. Two years later, patient "Number Four" was checked again and he was still disease free.

However, the first three patients, who received a smaller dose, had no response at all. Some other patients who received the same dose didn’t respond as well as patient number 4 did, but did saw some improvement.

Steven Rosenberg, chief surgeon at the National Cancer Institute, described the form of treatment as “the ultimate personalized medicine,” but also added that the fact that it’s a labor intensive treatment doesn’t make very attractive to commercial development.

The results of the study have been published in this week's issue of the New England Journal of Medicine, and are the latest findings in the field of "adoptive immunotherapy," a theory according to which the human body can be taught to fight off its own cancers.