Myeloid Neoplasma with Eosinophilia (MLN-Eo) with Rearrangement of ETV6-ABL1D72.1, C47.5

Myeloid neoplasms with eosinophilia are a clinically, morphologically, genetically, and prognostically heterogeneous group of clonal diseases characterized as follows:

• Initially, a persistent proliferation of clonal eosinophilic granulocytes in the peripheral blood.
• a hypercellular bone marrow
• if necessary, splenomegaly (Valent Pet al. 2012).

In morphology, the assessment of qualitative and quantitative changes in the non-eosinophil series (megakaryocytes, monocytes, mast cells, blasts) and bone marrow fibrosis is significant. By means of molecular genetic investigations, cytogenetic aberrations (e.g. reciprocal translocation, deletion, inversion, trisomy, complex karyotype), rearrangements of genes (FISH analysis), fusion genes (FISH analysis, RT-PCR) or mutations (allele-specific PCR, NGS) are included in the diagnosis. The causative genetic aberrations are characterized by a varying risk of progression to a myeloid or lymphoid blast phase (with a corresponding unfavorable prognosis).

In myeloid neoplasia with eosinophilia (MLN-Eo) with rearrangement of ETV6-ABL1, the ETV6-ABL1 fusion gene always underlies a more complex event with at least 3 chromosomal breaks in the region of chromosome bands 9q34 and 12p13 due to the orientation of the genes.

The ETV6-ABL1 fusion gene is associated with a broad spectrum of myeloid and lymphoid neoplasms. ETV6-ABL1 positive de novo ALL is found mainly in children (Zaliova M et al. (2016).

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