13 - Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions

Abstract

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK) are a family of myeloid or lymphoid neoplasms resulting from tyrosine kinase gene rearrangement. These neoplasms are commonly associated with eosinophilia and sensitivity to tyrosine kinase inhibitors. They can present as myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), acute myeloid leukemia (AML), mixed-phenotype acute leukemia (MPAL), B- or T-acute lymphoblastic leukemia/lymphoma (ALL). The defining genetic lesions include rearrangements involving tyrosine kinase genes commonly involving PDGFRA, PDGFRB, FGFR1, JAK2, FLT3, and ETV6::ABL1 fusions. This chapter uses several clinical cases to demonstrate how the identification of tyrosine kinase gene fusions by chromosome analysis, FISH, and NGS helps clinical diagnosis of these neoplasms.