Predictive and Prognostic Biomarkers in Myeloid Neoplasms

Abstract

The major categories of myeloid neoplasms include myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), myelodysplastic/myeloproliferative neoplasms (MDS/MPN, acute myeloid leukemia (AML), mastocytosis, blastic plasmacytoid dendritic cell neoplasms, and myeloid/lymphoid neoplasms with eosinophilia. MPNs are stem cell disorders characterized by proliferation of cells of one or more of the myeloid lineages (granulocytic, erythroid, and megakaryocytic) and a tendency to transform to acute myeloid leukemia. Dysregulation of JAK2 signaling by direct or indirect mechanisms has emerged as the central theme in classic MPNs leading to the use of JAK2 inhibitors for therapy. MDS are clonal hematopoietic neoplasms characterized by simultaneous proliferation and apoptosis of hematopoietic cells that results in a normocellular or hypercellular marrow with peripheral blood cytopenias and a tendency to evolve into acute myeloid leukemia. Sequential acquisition of somatic mutations in a set of genes involved in hematopoiesis leads to dysregulation of cellular processes leading to asymptomatic clonal hematopoiesis and later to MDS. MDS/MPNs include clonal myeloid neoplasms, which at the time of initial presentation are associated with features that support the diagnosis of MDS and other findings more consistent with an MPN. AML results from the clonal expansion of myeloid blasts in the peripheral blood, bone marrow, or tissues. Mutations in the epigenetic pathway including genes such as DNMT3A, ASXL1, TET2, and IDH1/IDH2 are acquired early in the disease process. Mutations involving the signal transduction pathway or NPM1 are typically secondary events that occur later during the evolution of the disease. Inhibitors of FLT3 and IDH1 and IDH2 are currently used for targeted therapy.