When stem cells go bad
Play lead role in brain tumours; The discovery is seen as a major
advance in the understanding of cancer

MARGARET MUNRO
CanWest News Service


Thursday, November 18, 2004


Stem cells, which are believed to hold great medical promise, also play
a lead role in fuelling the formation and growth of brain tumours.

The discovery by University of Toronto researchers is seen as a major
advance in the understanding of cancer, and brain tumours in particular,
which are among its deadliest forms.

It also opens the door for new treatments, and might make it possible to
tailor therapies to attack the stem cells driving cancers, said Peter
Dirks, head of the team reporting the finding in the journal Nature
today.

The researchers, working at Toronto's Hospital for Sick Children,
suspected there was something particularly lethal about a subgroup of
cells - which they identified as abnormal stem cells - found in human
brain tumours.

To prove their theory, they took cells from human tumours and injected
them into the brains of mice. The transplanted cells soon grew into
replica brain tumours.

"They look almost identical to the patient's original tumour," Dirks
said.

The researchers then took cells from the tumours that grew in the mice
and transferred them from mouse to mouse, where more identical tumours
formed.

As few as 100 transplanted cancer stem cells were enough to generate new
tumours.

The discovery might explain why cancers can return with such vengeance,
even after surgery and chemotherapy have eradicated all visible signs of
the disease, he said.

Stem cells are potent "master" cells found around the body that have the
capacity to grow into many different types of cells.

Research teams around the world are racing to explore and exploit the
potent cells. They hope to harness stem cells and use them to repair and
regenerate everything from damaged hearts to broken spines and impaired
eyesight.

© The Gazette (Montreal) 2004








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