FGFR1 and myeloproliferative neoplasm: Similar to other MLN-TK, FGFR1 rearrangements can present with varying phenotypes and clinically manifested as B-cell or T-cell lymphoblastic leukemia/lymphoma, AML, mixed phenotype leukemia, MPN, or MDS/MPN due in part to the different FGFR1 fusion partner genes and their effect on the intracellular signaling pathways.