By Peter W. Andrews, D.Phil.

The International Stem Cell Initiative is a consortium of researchers from around the world and funded by the International Stem Cell Forum, a grouping of funding agencies interested in supporting human embryonic stem (ES) cell research. In the first Initiative, the markers expressed by human ES cells were examined, confirming that the lines isolated in different laboratories are broadly similar, as well as identifying standard markers for human ES cells. A second Initiative has compared the media used for human ES cell culture and is assessing the common genetic changes that occur in human ES cells on prolonged culture. A further Initiative is now in progress to reach a consensus on functional tests to assess the degree of pluripotency of human ES and iPS cells. The activities of the Initiative were cemented by a series of informal workshops for participating researchers, held at the Jackson Laboratory in Bar Harbor, Maine.