London, June 19 : A team of US researchers claims to have successfully treated a skin cancer patient with cells cloned from his own immune system.
Researchers at the Fred Hutchinson Cancer Research Center in Seattle took cancer-fighting immune cells, made five billion copies, then put them all back.
The 52-year-old patient was free of his advanced melanoma two years after the groundbreaking treatment.
During the treatment, researchers concentrated on a type of white blood cell called a CD4+ T cell.
From a sample of the man's white blood cells, they were able to select CD4+ T cells, which had been specifically primed to attack a chemical found on the surface of melanoma cells.
These were then multiplied in the laboratory, and put back in their billions to see if they could mount an effective attack on the tumours.
After two months, researchers found that the tumours had disappeared, and two years later, the man remained disease-free.
The also found that the new cells persisted in the body for months after the treatment.
However, the researchers pointed out that their technique applied only to a 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.
"For this patient we were successful, but we would need to confirm the effectiveness of therapy in a larger study," BBC quoted Dr Cassian Yee, who led the project, as saying.
Even scientists in the UK have warned that further trials would be required to prove how well the treatment worked.
A spokesman for Cancer Research UK said: "This is another interesting demonstration of the huge power of the immune system to fight some types of cancer.
"Although 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 for the work that ourselves and others are carrying out in this field," he added.