Specifically, Dr. Mick Bhatia of Hamilton's McMaster University and his team have demonstrated for the first time how to tell the difference between normal stem cells and cancer stem cells in humans.

"Normal stem cells and cancer stem cells are hard to tell apart, and many have misconstrued really good stem cells for cancer stem cells that have gone bad — we now can tell the ones masquerading as normal stem cells from the bad, cancerous ones," Dr. Bhatia, scientific director of the Stem Cell and Cancer Research Institute at McMaster University in Hamilton, Ontario.

The research also helps allay one of the big worries about one day using stem cells to grow new organs and other tissues for curing disease — that the stem cells could give rise to tumours and end up doing more harm than good.