Stem-Cell Breakthroughs Announced

December 7, 2007


A pair of teams recently published independent reports confirming the creation of pluripotent human stem cells using non-embryonic tissue. Researchers at the University of Wisconsin in Madison and Kyoto University in Japan used a small number of gene factors to turn human skin cells into pluripotent (universally adaptable) stem cells, which then developed into bone, brain and heart tissue in culture. The US research was led by James Thomson, PhD, and Junying Yu, PhD, while the Japanese research was led by Shinya Yamanaka, MD.

Previously, the only source for pluripotent stem cells was human embryos. In addition to highlighting a way past an ethical conundrum, the new methods also lead to the creation of cells that match their donors' genetics—an important consideration in preventing host rejection. However, one research team encountered a risk of tumors in its test subjects, and both teams remain committed to finding ways to produce stem cells without the introduction of gene factors via retroviruses, a pair of necessities whose long-term impacts are not yet clear.

Both Thomson and Yamanaka called for embryonic stem-cell research to continue in the wake of their work. Thomson, the first scientist to isolate human embryonic stem cells in 1998, said in a December 2 Washington Post column that their work is too new to preclude the need for further research on all stem-cell fronts. This view is consistent with the Academy's position statement on stem-cell research, which calls for ongoing research on both fronts, as well as frequent and careful review of medical science.

For more information on the Academy's advocacy efforts regarding stem-cell research, contact Amy Kaloides at