While stem cells found in the blood and bone marrow, so-called hematopoietic stem cells, have been studied for 20 years, more primitive stem cells obtained from embryos have revolutionized stem cell research, says Civin, professor of oncology at the Johns Hopkins Kimmel Cancer Center.
Previewing the discussion, Civin says that "until 1998, 'stem cells' were hematopoietic stem cells; no other kind was known in people. Now, the potential of stem cells from embryos to shed light on basic biology, human development and genetic diseases, and to someday offer ways to treat incurable and fatal diseases has made us re-examine what we think we know about stem cells from the blood and other tissues."
Blood-forming stem cells and other more specialized stem cells from specific tissues or organs are known as "adult" stem cells even if found in newborns or children. Darwin Prockop, from the Gene Therapy Center at Tulane University Medical Center, will recap advances with adult stem cells, which seem to be capable of becoming more cell types than once thought. Irving Weissman, from Stanford University, will discuss the current status of embryonic stem cell research and where it is heading.
"Right now, scientists are just learning about the biology of human embryonic stem cells and how to grow them reliably -- things we've known about hematopoietic stem cells for 20 years or longer," says Civin. "But embryonic stem cells are ahead of adult stem cells in making a wide variety of different cell types on demand."