September 19, 2005

TORONTO -- On the surface, at least, they seem an unlikely duo: one, the offspring of a Toronto physician, educated at Ontario's tony Upper Canada College; the other, the son of a Saskatchewan farmer, who attended local public high school. Ernest McCulloch followed his father into medicine; James Till veered sharply from his roots to become a biophysicist.

But what the two men share is a passionate devotion to science -- and their serendipitous pairing led to a discovery that laid the foundation for what may be the most promising and ethically controversial area of international medical research today.
That discovery was recognizing the first stem cell, an entity that had been theorized about since the early 1900s, but never found until Dr. McCulloch and Dr. Till made the intellectual leap in the early 1960s while experimenting with bone marrow in laboratory mice.
Dubbed the fathers of stem-cell research, the long-term colleagues will be honoured Friday in New York with the 2005 Lasker Award for basic medical research, sharing a prize of $50,000 (U.S.). The Laskers, referred to as "America's Nobels," have often been prescient: 70 of its winners have gone on to win Nobel prizes, 19 in the last 15 years.

The Lasker is the latest in a long list of honours for Dr. Till and Dr. McCulloch, including being named Officers of the Order of Canada and inducted into the Medical Hall of Fame.
But true to their belief in scientific integrity, and in perhaps typically Canadian fashion, they steadfastly refuse to overstate their contribution to medical history.
"It's a surprise and a thrill," Dr. McCulloch, 79, said of the award during an interview with Dr. Till at Princess Margaret Hospital in Toronto, where they remain semi-retired senior scientists at the centre's Ontario Cancer Institute.
"After 40 years, I think it means our work has stood the test of time reasonably well," added Dr. Till, 74.
As with many great partnerships, their pairing came about more by accident than design.
Dr. McCulloch wanted to investigate how injected bone marrow would affect lab mice that had undergone lethal doses of radiation.
"And Dr. [Harold] Johns wasn't going to allow any mere physician to have anything to do with his radiation devices," Dr. McCulloch said of the Canadian who invented the Cobalt-60 radiation machine to treat cancer.
"He asked for volunteers to do the radiation of the mice, and Dr. Till volunteered. And once we began working together, it was no longer Dr. Till doing radiation and me doing bone-marrow function. We were both doing everything and have been doing everything together really ever since, although in different ways."
During one experiment, they discovered lumps of cells scattered over the animals' spleens -- the number of which exactly matched the number of marrow cells they had injected.
What was born from that eureka moment 45 years ago was a shift in emphasis from trying to "see" stem cells, which are rare (maybe one in 1,000 cells) and by microscope look much like any other cell.
"We had switched the focus from what might they look like to what can they do," Dr. Till said. "That was, I believe, our major contribution, to say: 'Forget it. Who cares whether they're purple or not. Let's focus on what they can do.' "
Today, stem cells from blood, tissue and embryos are seen as the great hope of medicine, whether as the key to understanding how to defeat many cancers to regenerating disease-ravaged organs like hearts and livers and even parts of the brain.