William E. Evans is recognized for his research on the pharmacogenomics of leukemia treatment in children. His lab elucidated the pharmacodynamics of methotrexate treatment of acute lymphoblastic leukemia and discovered the genetic basis for inherited differences in the enzyme thiopurine methyltransferase and defined its role in determining the risk of hematopoietic toxicity in patients treated with mercaptopurine and azathioprine. More recently, his lab has used genomewide strategies to elucidate the importance of both inherited and somatic genome variation in determining the efficacy and toxicity of leukemia chemotherapy. He has been funded by 3 successive NIH MERIT awards and has produced over 400 research publications. He served as CEO of St. Jude Children’s Research Hospital in Memphis TN (USA) from 2004-2014, and was elected into the IOM of the National Academy of Sciences in 2002 and the US National Academy of Medicine in 2015.