Rates of the deadliest form of skin cancer could triple in the next 30 years if Britons do not protect themselves from the sun’s harmful rays, scientists said on Wednesday.

More than 7,300 cases of malignant melanoma are diagnosed each year in Britain and 1,700 people die of the disease but Professor Brian Diffey, of Newcastle General Hospital in northern England, said many cases could be prevented.

“If present rates of melanoma continue, as they have done in the last 25 years, then in 30 years time the rates are predicted to be three times what we see today,” Diffey told Reuters.

“We’re seeing an ever-upward rise.”

He said it is essential that people monitor moles and skin blemishes and report any changes in them because detecting the disease early is vital.

Malignant melanoma accounts for roughly 10 percent of reported cases of the illness. About 133,000 new cases of the disease are diagnosed worldwide each year.

It usually develops in cells in the outer layer of the skin but can spread to other parts of the body, forming secondary tumors.

Melanoma is the second most common cancer among people aged 15-34. Researchers say sunburn in childhood can double the risk of melanoma in later life.

People are advised to stay out of the midday sun, avoid sunburns and wear sunscreen, wide-brimmed hats and sunglasses.

“We know that half of all cases of cancer can be prevented by making lifestyle changes. We’re seeing more and more people giving up smoking to lessen their chances of getting a whole range of cancers,” said Professor Robert Souhami, of Cancer Research UK which has launched a campaign to raise awareness about skin cancer.

“Reducing the risk of skin cancer is something most of us can do,” he added in a statement.