Myeloid neoplasms (MN), including acute myeloid leukemia and myelodysplastic syndrome, are lethal blood cancers. The genetic mutations in the blood that lead to MN can occur years before diagnosis and maintain almost normal function before transformation. Certain mutations, including those in the gene IDH2, have been identified as high-risk for developing MN. Individuals with a reduction in the number of mature blood cells (cytopenias) who harbor acquired mutations in their blood, yet do not meet criteria for a cancer diagnosis, have a condition called cytopenias of undetermined significance (CCUS). These individuals almost invariably develop MN. Dr. Bolton will conduct a clinical trial to evaluate whether the IDH2 inhibitor enasidenib can be used as a therapy for CCUS. She will assess mechanisms of resistance and determine whether enasidenib can prevent the development of MN. This represents the first use of genetically targeted therapy for cancer prevention.