Work

Comprehensive response criteria for myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions: a proposal from the MLN International Working Group

Year: 2023

Type: article

Abstract: In 2008, in response to the identification of patients with “chronic eosinophilic leukemia” or “hypereosinophilic syndrome” who carried recurrent tyrosine kinase fusion genes involving PDGFRA , PDGFRB , or FGFR1 , the World Health Organization classification of myeloid neoplasms included a new category termed “Myeloid/lymphoid neoplasms (MLN) with eosinophilia and rearrangements of PDGFRA, PDGFRB , or FGFR1 ” [ 1 ]. This World Health Organization category was revised in 2016 with the addition of PCM1::JAK2 as a provisional entity [ 1 ]. In the recent fifth edition of the World Health Organization classification, similar to the recent update to the International Consensus Classification, the category was renamed to “myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions” and both classifications added novel subtypes with new JAK2 rearrangements (e.g., BCR::JAK2 , ETV6::JAK2 ) as well as fusions involving FLT3 , and the ETV6 :: ABL1 fusion [ 2 , 3 ]. Although eosinophilia (>0.5 × 10 9 /l) or hypereosinophilia (>1.5 × 10 9 /l) are characteristic of this subgroup, they are not universally present [ 4 ]. The clinical phenotype is largely influenced by the involved tyrosine kinase fusion gene and/or the fusion partner gene [ 5 , 6 ]. For example, most patients with the FIP1L1::PDGFRA fusion gene present with a chronic myeloid neoplasm with eosinophilia; however, mixed lineage presentations are more common in patients with FGFR1 fusions [ 5 , 6 , 7 , 8 ]. Furthermore, in MLN with FGFR1 rearrangements, translocations involving ZMYM2 are more commonly associated with a T-lymphoblastic lymphoma phenotype, whereas translocations involving BCR tend to lead to a phenotype resembling BCR::ABL1 positive chronic myeloid leukemia [ 5 , 6 , 9 ].

Source: Leukemia

DOI: 10.1038/s41375-023-01859-3