The 8p11 myeloproliferative syndrome: a review of recent literature

Abstract

The 8p11 myeloproliferative syndrome (EMS) is a relatively rare hematological malignancy defined by the presence of chromosomal abnormalities associated with fibroblast growth factor-1 gene, located in the 8p11-12.1 chromosomal locus. To date, only around a hundred cases have been reported in the literature. Patients with EMS present with various forms of myeloid/lymphoid malignancies, such as myeloproliferative neoplasms, acute myeloid leukemia, and T- or B-linage lymphoblastic lymphoma, which are frequently associated with eosinophilia. Prognosis of EMS is poor and a standard treatment strategy has not yet been established. In contrast to myeloid/lymphoid neoplasms associated with PDGFR-A or PDGFR-B rearrangement, the tyrosine kinase inhibitor (TKI) imatinib is not an effective therapeutic option for EMS patients. Other types of TKI, i.e., PKC412, sorafenib, ponatinib, dasatinib, and dovitinib, show growth-inhibitory effects against the cells harboring several types of FGFR-1 fusion genes in in vitro studies; however, the usefulness of either drug has not been confirmed by clinical trials. Therefore, at present, allo-hematopoietic stem cell transplantation is the only curative methods for EMS. Very recently, a phase-2 study with pemigatinib, an inhibitor for FGFR1, showed clinical benefits for EMS patients, including major cytogenetic response, suggesting a new therapeutic option for EMS.