Short Sharp Science: 'Paradigm shift' in how we treat skin cancer

A new genetically targeted cancer drug has proven successful in treating malignant melanoma, the most dangerous type of skin cancer. Patients with advanced melanoma usually die within a year of diagnosis.

Over half of all people with melanoma carry mutations in the B-RAF gene that accelerates cancerous cell growth. The new drug, PLX4032, developed by US biotechnology company Plexxikon based in Berkeley, California, inhibits the mutated B-RAF gene, preventing it from stimulating cancerous growth.

In 24 of the 32 participants with the mutated gene taking part in the phase 1 trials of the drug, the tumours shrank by 30 per cent, and in two people disappeared entirely.

Although scientists have known for some time that all cancers are a result of gene mutations, it is only recently that gene sequencing has become efficient enough to work out exactly what genetic differences give rise to cancer.

A study in Nature published last week described the drug's chemical structure and development, and raises hopes for the development of similar genetically targeted cancer drugs.

PLX4032 is not without side effects though, and melanoma tumours can become resistant to it. Researchers think that tumours may start re-growing about 7 months after therapy, so they are planning to test the drug in combination with others to see if they can prevent this from happening.

Nevertheless, PLX4032 has created a lot of excitement and the study has been described as the 'penicillin moment' in cancer research.

Richard Marais, a molecular biologist at the Institute of Cancer Research in London, who was not affiliated with the research, told Nature News that the drug had "spectacular" results. "There's been a paradigm shift in how to treat melanoma," he said.

"We really are at a remarkable moment," the Director of the Sanger Institute, Mike Stratton told the BBC. "Modern sequencing techniques give us the potential to identify all of the genetic mutations that give rise to cancer. We've entered the end game in which we're going to complete our understanding of what causes cancer."

Journal reference: Nature, DOI: 10.1038/nature09454