Scientists have successfully used gene therapy to alter the body's immune system and attack and destroy deadly skin cancer. In the experimental medical treatment, two of the 17 patients with advanced melanoma tested cancer-free more after than 18 months of the gene-therapy.

"Given all the hype of gene therapy...this is one of the first that has the potential to be applied to common cancers," said Steven Rosenberg, the lead researcher and chief of surgery at the National Cancer Institute.

In gene therapy, genes are inserted into an individual's cells and tissues to treat a disease, usually and hereditary. Gene therapy aims to supplement mutations in DNA that impair the body's natural function.

Rosenberg's technique uses infection-fighting white blood cells called T-cells from the patients modified to produce a protein receptor called T-cell receptor. The receptor allows them to latch onto the tumours so the white blood cells can kill the cancer. Why only two out of the 18 treated patients benefitted from the treatment remains unexplained.

The American Cancer Society estimates more than 8,000 people in North America will die from skin cancer this year.