Skin cancer sufferers could be cured of the disease with new breakthrough drugs, experts claimed, as they hailed the "beginning of a new era".
Seriously ill patients are said to have seen "spectacular effects" after receiving the medication which could eventually be used to combat other forms of the condition.
It is the first time scientists have come this close to providing a remedy for advanced melanoma.
The development will bring hope to thousands of people who are diagnosed with skin cancer in Britain each year.
Until now the prognosis for advanced melanoma has been very poor and many patients die within months of diagnosis.
Professor Peter Johnson, chief clinician at Cancer Research UK, said: "We're just at the beginning of a new era of cancer treatments using the immune system.
"These drugs that can turn the body's own defences against a tumour are starting to show real promise for melanoma and other types of cancer.
"It's only through research that we can gain the insights needed to develop new treatments for cancer patients."
The new cure contains two types of drug - ipilimumab (known as ipi) and anti-PD1s which break down the defences of cancer cells and are still in clinical trials.
Doctors can effectively reboot a patient's immune system by combining the two.
One in six patients are already being saved by the ground-breaking treatment, the European Cancer Congress has been told.
A new combination of drugs could mean more than half are cured of the deadly condition.
Professor Alexander Eggermont of the Institut Gustave Roussy in France said: "Advanced] melanoma could become a curable disease for perhaps more than 50% of patients within five to 10 years."
"If I'd made this bizarre prediction five years ago, people would have said I was mad," he told The Mail on Sunday.
"But it now looks like we are going to have control of advanced melanoma for years, in a substantial proportion of patients."
Advanced melanoma is diagnosed when the disease has spread and can no longer be surgically removed.
Advice on the Cancer Research UK website currently warns patients that this form of skin cancer " can't be cured".
It states: "Treatments are available that can shrink the melanoma or stop it growing. It may be possible to control it for quite a while."