Next-generation sequencing in two cases of de novo acute basophilic leukaemia

Approach to Acute Myeloid Leukemia with Increased Eosinophils and Basophils

There is remarkable morphologic and genetic heterogeneity in acute myeloid leukemia (AML). In a small percentage of cases of AML, increased eosinophils and/or basophils are present in the bone marrow and sometimes in the peripheral blood. This is often a puzzling diagnostic situation but also an important finding that requires special investigation. Unique chromosomal rearrangements have been correlated with an increased number of eosinophils and basophils in AML. The identification of the underlying genetic lesion that promotes eosinophilia and basophilia can dramatically change both the prognosis and the treatment of the patient. Thus, clinicians must be vigilant in searching for the cause of eosinophilia and basophilia in patients with AML, since the different causes may lead to different treatments and survival outcomes. In this article, we examine the significance of increased eosinophils and/or basophils in the context of AML, provide guidance that simplifies the differential diagnosis, and give prognostic and therapeutic information about specific subtypes of AML associated with eosinophilia and/or basophilia. Evidence supporting personalized (molecularly targeted) therapy for these patients is also presented.

Next-generation sequencing in two cases of de novo acute basophilic leukaemia

Acute basophilic leukaemia (ABL) is a rare subtype of acute myeloid leukaemia (AML); therefore, few data are available about its biology. Herein, we analysed two ABL patients using flow cytometry and next‐generation sequencing (NGS). Two cell populations were detected by flow cytometry in both patients. In Case no. 1, blasts (CD34⁺, CD203c⁻, CD117⁺, CD123dim⁺) and basophils (CD34⁻, CD203c⁺, CD117^±, CD123⁺) were identified, both of which were found by NGS to harbour the 17p deletion and have loss of heterozygosity of TP53. In Case no. 2, blasts (CD33⁺, CD34⁺, CD123⁻) and basophils (CD33⁺, CD34⁺, CD123⁺) were identified. NGS detected NPM1 mutations in either blasts or basophils, and TET2 in both. These data suggest an overlap of the mutational landscape of ABL and AML, including TP53 and TET2 mutations. Moreover, additional mutations or epigenetic factors may contribute for the differentiation into basophilic blasts.