A novel ETV6::FGFR1 fusion gene in a myeloid/lymphoid neoplasm with FGFR1 rearrangement sensitive to specific FGFR1-2-3 inhibition

Abstract

Myeloid/lymphoid neoplasms with FGFR1 rearrangement (FGFR1r) are rare entities, characterized by the aberrant expression of the tyrosine kinase involving the fibroblast growth factor receptor 1 (FGFR1) in a pluripotent, both myeloid and lymphoid, progenitor cell1. Clinical and hematological features are determined by the partner gene involved where patients with the same fusion gene tend to present a similar disease phenotype. Prognosis is poor and patients have an aggressive course, being allogeneic hematopoietic stem cell transplantation the only curative treatment nowadays2.Herein, we describe a myeloid/lymphoid neoplasm with ETV6::FGFR1 rearrangement refractory to intensive salvage chemotherapy, which showed response to specific inhibition of the abnormally activated FGFR1 tyrosine kinase with pemigatinib, a panFGFR1-2-3 inhibitor. To our knowledge, this is the first report of a myeloid/lymphoid neoplasm with FGFR1 rearrangement involving ETV6 as partner.