Dr. Williams major research interests are in the study of blood stem cell biology, blood formation, leukemia and the treatment of genetic blood diseases using gene therapy. He has published over 250 peer-reviewed manuscripts and textbook chapters. He was an investigator of the HHMI for 16 years. He has been continuously funded by the NIH since 1986. His laboratory co-discovered and cloned Interleukin-11 (Neumega TM) and carried out developmental studies that assisted in obtaining FDA approval of this drug. His laboratory also described and patented the use of fibronectin in retrovirus-mediated gene transfer, now nearly universally used (as Retronectin TM) in clinical gene therapy trials and basic research utilizing gene transfer. His most recent focus has been on exploring the role of Rho GTPases in hematopoietic stem cell biology. He and Dr. Yi Zheng have developed a new small molecule inhibitor of Rac GTPases that is being investigated collaboratively in cancer therapies. Thus, work in the Williams laboratory has led to multiple patents and product licenses for new therapies in human diseases. He also leads several gene therapy trials in immunodeficiency and neurologic disease.