High-throughput sequencing and microarray technologies have been used for comparative analyses of circRNAs between PBMCs or BM from patients with acute myeloid leukemia (AML) and controls for different settings: 1) with and without extramedullary infiltration (94, 95), 2) with WT and mutated nucleophosmin 1 (NPM1) (96), 3) positive or negative for Fms-related receptor tyrosine kinase 3–internal tandem duplication (FLT3-ITD) mutations, and 4) in doxorubicin-sensitive and -resistant AML cell lines (97, 98). The gene discussed is FLT3; the disease is acute myeloid leukemia.