EDINBURGH author JK Rowling, the creator of the Harry Potter novels, has revealed that a pioneering centre for cancer patients may have saved her friend's life.

The writer was the guest of honour at a glittering ball held at the Sheraton Hotel on Saturday to raise money for Maggie's Centre at Edinburgh's Western General Hospital.

The author of the phenomenally successful novels about a schoolboy wizard told guests of her own family's pain at losing five relatives to cancer.

And she spoke movingly of her belief that Maggie's had helped to save the life of one of her best friends, Patricia, who she met after moving to Edinburgh three years ago.

She said one day, she went to see Patricia and found her "planning her funeral" after receiving a "brutal" diagnosis of secondary breast cancer.

Ms Rowling added that Maggie's Centre may even have saved Patricia's life, and said she was proud that the centre had been pioneered in Edinburgh.

"Maggie's Centre certainly improved her quality of life and I believe may even have saved her life," she said.

"I can think of no cause more worthy of support."

Single mum Ms Rowling, 34, who penned the first Harry Potter book, The Philosopher's Stone, in a city cafe while struggling to get by on income support, also lent her support by bidding successfully for two lots in the charity auction held after the dinner, which raised GBP 12,000.

She bid GBP 500 for a round of golf with rugby heroes Tony Underwood and Doddie Weir, and paid GBP 1300 for a two-night stay at Champney's Health Spa.

Social Security Secretary Alistair Darling and Liberal Democrat MP Menzies Campbell also offered auction prizes of guided tours of the House Of Commons, which raised GBP 900.

The money raised at the dinner will contribute to the centre's annual running costs of GBP 200,000.

But the centre's assistant director, Barbara Kidd, said Ms Rowling's support had been an "enormous boost" to the Evening News appeal to raise GBP 100,000 towards the expansion of the centre.

"There is no doubt the appeal to help build the extension brought 300 people out at the weekend," she said.

Ms Kidd added: "Ms Rowling gave a very moving account of her friend. Although she was still being treated for cancer the woman said through her visits to Maggie's her quality of life had been much improved.

"She said her friend had a much more positive outlook on life, knowing she had the support of the centre to fall back on.

"We hope, through this appeal, to be able to do that for many, many more cancer sufferers."

With the appeal fund just over half way towards its GBP 100,000 target, Ms Kidd said she was confident users of the centre at the Western General Hospital would be using the new facility next spring.