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To allow scientists to select which lines are most suitable for their intended experiments, the research community has consistently requested that available cell lines be more fully characterized.

To address this important need, the NIH Intramural Research Program has created the NIH Stem Cell Unit. The purpose of the Unit is to have a side-by-side comparison of the available human embryonic stem cell (hESC) lines on the NIH Human Embryonic Stem Cell Registry. The Unit's main goal is to identify—and share with the research community—the similarities and differences between the available hESC lines when subjected to a standardized paradigm.

Performing these assays in a single laboratory will allow a direct, side-by-side comparison to be made among the cell lines that are available for shipment and will facilitate comparison with adult stem cells. These data will give the scientific community information about the properties of available lines, so scientists can make an informed choice when ordering one or more of the available cell lines.

Data will be regularly posted on this Web site as soon as they have been validated. The assays performed by this Unit will be overseen by a steering committee of leading stem cell biologists in both the extramural and NIH intramural research community. Ronald D. G. McKay, Ph.D., will provide day-to-day direction for this unit.