The enzyme TET2 controls how blood stem cells produce healthy blood cells. TET2 is frequently mutated in blood cancers, so understanding its functions in blood stem cells can help in designing cancer drugs for patients with mutated TET2. In a study involving TET2 mouse models published online on September 3 in Cell Reports, Keisuke Ito, M.D., Ph.D., and Meelad Dawlaty, Ph.D., report that TET2’s catalytic action suppresses  myelodysplastic syndrome (MDS) and myeloid cancers, while—through non-catalytic means—TET2 prevents lymphoid cancers such as B-cell leukemia. Drs. Ito and Dawlaty also received a four-year, $2.8 million grant from the National Heart, Lung, and Blood Institute to conduct further research into TET2’s roles during normal and abnormal blood cell formation. Dr. Ito is director of scientific resources of the Stem Cell Institute and associate professor of cell biology and of medicine at Einstein, while Dr. Dawlaty is an assistant professor of genetics and member of the Einstein Stem Cell Institute. (R01HL148852)