US scientists have found a gene that drives the growth and survival of the most dangerous form of skin cancer.
Skin cancer rates have been increasing across the UK
Every year, more than 7,000 UK people are diagnosed with malignant melanoma and about 1,700 die from it.
Experts have warned that annual UK rates could treble by 2035 based on current trends.
The gene discovery, described by the Dana-Farber Cancer Institute team in the latest edition of Nature, could point to new treatments, they hope.
Dr Levi Garraway and colleagues used a high tech procedure that focuses on the building blocks of individual genes to identify areas of DNA containing mistakes in tissue samples from patients with malignant melanoma.
By comparing these with results from non-cancerous tissue samples, they pinpointed one genetic error that appeared to be critical for tumour growth, particularly in some of the most advanced cancers that had spread or metastasised.
This was an abnormal replication or amplification of a gene called MITF. Some tumours had as many as 13 extra copies of MITF.
Co-researcher Dr William Sellers said: "By pinpointing the abnormally multiplied MITF oncogene, we may be able to develop better diagnostic and prognostic tools as well as provide a target for highly specific therapies for metastatic melanoma patients who have this overcopied gene."
The abnormal amplification of the MITF gene was associated with other genetic changes as well. They included mutations in a gene previously found in malignant melanomas, called BRAF, and silencing of a gene that normally keeps cells from dividing too rapidly and causing cancer, called p16.
Dr Sellers said: "We might be able to treat these metastatic melanomas by targeting the MITF gene or protein, alone or in combination with drugs that block BRAF."
Ed Yong, Cancer Information Officer at Cancer Research UK, said: "Excessive sun exposure causes most cases of melanoma. But faults in some genes can influence our risk of this disease, and our chances of surviving it.
"Identifying these genes can suggest new ways of preventing or treating this cancer."