Three separate studies involving stem cells were published by Stanford researchers this week, lending insight into cancers, aging and the detection of stem cells in living organisms.

Enabling and promoting scientific work on stem cells at Stanford has been the function of the Stanford Institute for Stem Cell Biology and Regenerative Medicine. The Institute, a component of the Medical School, received a $33 million gift from donor Lorry Lokey '49 earlier this year that will help fund construction of a new research building.

The journal Nature published a study yesterday that found aging stem cells may explain the onset of blood disorders like leukemia in elderly individuals.

The study, led by Stanford Institute for Stem Cell Biology Director Irving Weissman, concluded that disorders like leukemia and anemia may be caused by the accumulation of genetic mutations in elderly stem cells, which were previously thought to escape such mutation by avoiding cell division. Cell division<\p>--<\p>a process in which DNA is copied for use in a second cell<\p>--<\p>is the step of the cell cycle most commonly associated with the introduction of genetic damage.

A second study identified the class of stem cells that cause tumors in colon and rectal cancer. The study was conducted by an interdisciplinary group of researchers led by Michael Clarke, associate director of Stanford's Institute for Stem Cell Biology, and lead author Piero Dalerba, a postdoctoral scholar. It was published in an early edition of the Proceedings of the National Academy of Sciences.

The tumor cells identified had unique surface proteins that could enable scientists to differentiate them from healthy cells, an important step that could lead to improved treatment options for the cancer.

Clarke, who previously identified the stem cells in breast cancer, head and neck cancers, and pancreatic cancers, said in a statement that the discovery could lead to the ability to conduct molecular studies crucial to the identification of new therapies. Irving and Dalerba concurred.

Researchers in a third study found that stem cells introduced into rats and mice were able to navigate toward areas of brain damage. The study, led by Gary Steinberg, a Stanford professor of neurosurgery and neuroscience, used magnetic resonance imaging (MRI) to track the cells, which were tagged with iron, as they traveled.

The stem cells were able to locate the areas of damaged tissue by following signals produced as a result of the damage. In rats with healthy brains, the stem cells stayed close to where they were injected.

Steinberg said in a release that the work is important because using iron and MRI is a method of tracking that does not interfere with the biology of the cells themselves. It could allow scientists to conduct clinical trials in people with brain damage caused by stroke disorders like Parkinson's disease, or traumatic brain injuries.