Molecular Characterization of Acute Erythroid Leukemia (M6-AML) Using Targeted Next-generation Sequencing

Acute erythroid leukemia (AEL) is a morphologically distinct, infrequent (o5%) acute myeloid leukemia (AML) designed as M6 in the French- American-British (FAB) classification. The World Health Organization classification recognizes two subclasses, M6a, a leukemia with myeloid blast cells, and M6b, a very rare, purely erythroid AML. It may be difficult to distinguish between a myelodysplastic syndrome and AEL because of the erythroblastic proliferation, which is increased when dysplasia is present. No recurrent cytogenetic abnormality is specific of AEL and the prognosis is poor with a median survival of 17 months. A study of 14 genes in a series of 92 cases has shown that mutations are frequent in AEL and somewhat differ from the other AMLs by the lower and higher proportion of FLT3-ITD and TP53 mutations, respectively. Only three cases of AEL are reported in the TCGA database. To further characterize AEL, determine whether it constitutes a distinct class of AML and document the reasons for its poor prognosis, the investigators will search for molecular alterations in 40 M6a-AMLs using array comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) of 106 genes known or suspected to have a role in myeloid malignancies or in erythrocyte differentiation.