Since cancer stem cells - and the implications for future cancer therapies - seem to be the topic of the moment, I should point out this news of progress from EurekAlert!: researchers "have isolated rare cancer stem cells that cause leukemia in a mouse model of the human disease. The leukemia stem cells isolated proved to be surprisingly different from normal blood stem cells - a finding that may be good news for developing a drug that selectively targets them. ... scientists showed that they could create leukemia stem cells, which also are self-renewing, from partially committed, non-self-renewing progenitor cells. The latter are short-lived cells that can turn into several types of blood cells ... in the future we should be able to specifically target leukemia stem cells without killing normal stem cells."