Crystal L. Mackall is Chief of the Pediatric Oncology Branch of the National Cancer Institute. She is Board Certified in Internal Medicine, Pediatrics and Pediatric Hematology/Oncology and has received international recognition for her work on T cell homeostasis and tumor immunology. She leads an active translational research program that incorporates basic studies of immunology with clinical trials of immunotherapy for pediatric cancer, with a special focus on pediatric sarcomas. She is the recipient of numerous awards including the NIH Distinguished Clinical Teacher Award in 2000, an NCI Mentor of Merit Award in 2003, and the NCI Director’s Award in 2003. She has authored over 100 scientific publications and is a member of the American Society of Clinical Investigation.