In the human breast, up to 20 per cent of all tumours are now suspected to originate in stem cells. Now scientists from the Icelandic Cancer Society and the Faculty of Medicine, University of Iceland have grown three-dimensional breast cell cultures to reveal unexpected subtleties about these stem cells that could explain why they spawn malignancies.

These stem cells, Valgardur Sigurdsson remarked during the EuroSTELLS Conference in Venice, Italy (19-21 March), could become targets for cancer treatment, leading to new therapies that wipe out cancer at its source. The hope is that they might also become useful tools to test new drugs.

"People have long suspected there should be a stem cell population in the human breast gland," said Sigurdsson who is part of the ESF-funded team led by Thorarinn Gudjonsson. A 'virgin' breast, before pregnancy, is very different to a fully functioning, milk-producing breast. With lactation, the breast becomes fully differentiated, and once this stage is over, it involutes. This cycle of proliferation, differentiation and apoptosis also happens in every menstrual cycle and in a more dramatic form during pregnancy. "This caught our attention, and has driven our research," Sigurdsson pointed out.

Breast cancer almost always occurs in the luminal epithelial compartment, which is also where milk is produced. Perhaps it is not surprising then, that stem cells reside in this compartment. In 2002, Thorarinn Gudjonsson, successfully isolated cells from the human breast with stem cell properties.

Gudjonsson immortalised these cells and grew them in three dimensional matrix that mimics the real, living tissue. Biologists have long relied on 2-dimensional cell cultures as the basic tool of their trade. But there is a big difference between a f
'"/>

Contact: Jens Persson
jpersson@esf.org
33-38-876-2158
European Science Foundation
24-Apr-2006