Human embryonic stem cells (ES cells) — cells obtained from an embryo when they are only a few days old — are unique because they can become any type of cell. They can also multiply in the laboratory for very long periods of time without losing this special ability. ES cells offer huge medical potential, both in research and clinical applications. They could, for example, be turned into cells affected by cancers, such as blood cells or brain cells, then genetically altered to become cancer-like and studied to identify potential drug targets or other unique characteristics. Human ES cells could also be used as a cell source for many different kinds of transplantation. One of the biggest hurdles to overcome in working with human ES cells is increasing understanding of how these cells turn into specific kinds of cells. Because they can become anything, ES cells often become many different things at once, which makes them difficult to study and potentially inappropriate for transplantation. A better understanding of the mechanisms an ES cell uses to turn into different kinds of cells would help ES cell differentiation be better controlled and directed towards cell types of interest. Building on her previous MSFHR-funded research, Melanie Kardel is researching how ES cells turn into blood cells. Kardel’s focus is on determining how many blood cells can be produced from a single ES cell, and what genes can influence either the number of blood cells produced or how long it takes to produce them. The research could contribute to more standard, controlled procedures for high efficiency blood cell production from human ES cells.