Scientists in the U.S. are claiming they have cured advanced skin cancer by using the patient's own cells.
The pioneering research used the patient's own cells which were cloned outside the body.
The researchers say they took cancer-fighting immune cells, made five billion copies, then put them all back and the 52-year-old male who had advanced melanoma which had spread to the lungs and lymph nodes, was free of melanoma two years after the treatment.
The body's immune system plays a significant role in the battle against cancer, and scientists have been searching for ways to boost this tumour-killing response.
The scientists from the Fred Hutchinson Cancer Research Center in Seattle concentrated on a type of white blood cell called a CD4+ T cell which they selected from a sample of the man's white blood cells.
CD4+ T cells were specifically primed to attack a chemical found on the surface of melanoma cells, then multiplied in the laboratory, and put back in billions to see if they could mount an effective attack on the tumours.
Within two months scans revealed the tumours had disappeared, and after two years, the man remained disease-free - the new cells persisted in the body for months after the treatment.
Though the research is a world first, the scientists say their technique only applied one patient with a particular type of immune system and tumour type, and could work for only a small percentage of people with advanced skin cancer.
Dr. Cassian Yee, who led the research says the effectiveness of the therapy needs to be confirmed in a larger study.
Cancer experts say the research provides another interesting demonstration of the huge power of the immune system to fight some types of cancer but they also say more research is needed.
They say though the technique is complex and difficult to use for all but a few patients, the principle that someone's own immune cells can be expanded and made to work in this way is very encouraging.
Advanced malignant melanoma is the most dangerous form of skin cancer and is notoriously hard to treat once it starts to spread.
Experts suggest the treatment may have caused the patient's immune system to broaden out and recognise other tumour antigens and they say the treatment could be used for 25 per cent of late-stage melanoma sufferers with the same profile as the trial patient.
The research is published in the New England Journal of Medicine.