Two Toronto scientists whose discovery of stem cells paved the way for controversial research are said to be candidates for the 2009 Nobel Prize in medicine, the winners of which will be announced Monday.

James Till, left, and Ernest McCulloch, pose for a photo after receiving the 2005 Lasker Award for Basic Medical Research in New York City on Sept. 23, 2005. (John Smock/Associated Press)

Ernest McCulloch and James Till won the prestigious Lasker Award in 2005 and experts say they could also be among the front-runners for a Nobel for their early 1970s identification of the regenerative cells. Many winners of the Lasker Award — often dubbed "America's Nobel" — go on to win Nobel Prizes.

Given their special abilities, stem cells offer the possibility to replace damaged cells, tissues and maybe organs to treat diseases such as Alzheimer's, heart disease, diabetes, or rheumatoid arthritis.

Growing stem cells from human eggs has long been a controversial issue, but in a recent breakthrough scientists have managed to avoid the ethical quandaries by making human stem cells from ordinary skin cells.

Science writer Karin Bojs of Swedish daily Dagens Nyheter, who has stood out as a leading Nobel predictor over the years, included Till and McCulloch among her candidates for the prize this year.

Other potential winners include long-standing U.S. hopefuls Elizabeth Blackburn, Carol Greider and Jack Szostak for their enzyme research. The trio's discovery of the telomerases enzyme set the stage for research suggesting that cancer cells use telomerase to sustain their uncontrolled growth.

However, Bojs pointed out they could also be up for the Nobel Prize in chemistry because the line of distinction between the two awards is sometimes blurry.

Prize committee gives no hints about contenders

As usual, the tightlipped award committee is giving no hints about who is in the running before presenting its decision in a news conference at Stockholm's Karolinska institute.

The prize announcement is the first of six prizes focusing on medicine, physics, chemistry, economics, literature and the Peace Prize that will be announced through Oct. 12.

Alfred Nobel, the Swede who invented dynamite, established the prizes in his will in the categories of medicine, physics, chemistry, literature and peace. The economics prize is technically not a Nobel but a 1968 creation of Sweden's central bank.

Nobel left few instructions on how to select winners, but medicine winners are typically awarded for a specific breakthrough rather than a body of research.

Goran K. Hansson, new secretary of the medicine prize committee, said the 10 million kronor ($1.5 million Cdn) prize isn't necessarily awarded for discoveries that have already resulted in new medicines or other practical applications.

"The Nobel committee has often awarded discoveries long before they have come to practical use," he told The Associated Press. "It is gratifying and very positive if there are applications within medical care but it is the actual discovery that is being awarded."

He also said the committee doesn't consider the ethical implications of discoveries.

"We are awarding the discoveries and not the application and therefore those issues aren't of importance," he said, adding it is a very difficult job to pick a winner.

"There are so many beautiful discoveries made today that it is a delicate task to chose the most important."

The prizes are handed out every year on Dec. 10, the anniversary of Nobel's 1896 death.