Dr. Hatley is an Associate Member in the Molecular Oncology Division of the Department of Oncology at St. Jude Children’s Research Hospital. Dr. Hatley is a graduate of the University of Texas Southwestern Medical Scientist Training Program (MSTP). At UTSW, he completed his thesis work with Dr. Alfred G. Gilman defining the allosteric determinants of guanine nucleotide binding proteins. Following the completion of his MD and PhD degrees, Dr. Hatley remained at UTSW completing pediatric residency and then pediatric hematology and oncology fellowship. His fellowship included research in the laboratory of Dr. Eric Olson as a fellow of the Pediatric Scientist Development Program. In Dr. Olson's lab, Dr. Hatley determined the role of microRNA-21 in non-small cell lung cancer and characterized a novel model of pediatric embryonal rhabdomyosarcoma. In 2011, Dr. Hatley started his own research program at St. Jude Children’s Research Hospital to study how the cell of origin of rhabdomyosarcoma affects pathogenesis. The cell of origin is typically inferred from characteristics of the tumor cell. Dr. Hatley’s work illustrated that this can be dangerous assumption. Through genetic fate mapping in a genetically engineered mouse model of embryonal rhabdomyosarcoma, Dr. Hatley revealed that rhabdomyosarcoma, a tumor of presumed skeletal muscle origin, can originate from an endothelial progenitor cell. This work identified cell reprogramming or developmental transdifferentiation as a mechanism of transformation in pediatric sarcoma. His laboratory investigates how normal developmental processes are corrupted during transformation and establishes new rhabdomyosarcoma model systems to elucidate novel therapeutic vulnerabilities.