Human embryonic stem cells were successfully cultured in a lab for the first time in 1998. Scientists believe that transplanting these cells holds great promise for treating injury and disease because they have the unique ability to replicate themselves indefinitely and develop into a wide variety of other types of cells. But a number of challenges have to be tackled before stem cells can be safely used in the treatment of patients. These include understanding and being able to control how stem cells are transformed into other types of cells, overcoming immune rejection in patients receiving transplanted cells, and understanding any links between stem cells and the origin of cancer. Jaswinder Khattra is tackling a related challenge: defining the activity of novel genes and proteins in stem cells. Although thousands of human genes are known, many remain uncharacterized. Khattra is investigating the properties of novel genes discovered in stem cells to define how they act within the cells, and whether they play a role in controlling how stem cells differentiate into other cells. This research also examines the proteins produced by these genes and how they interact in regulating cell growth and function. Improved understanding of the molecular structure and function of these genes and proteins could contribute to improvements in cell-based therapies and drug screening for a range of diseases.