Chronic eosinophilic leukemia with erythroblastic proliferation and the translocation (8;9)(p22;p24) with PCM1-JAK2 fusion gene — a new clinical, pathological and genetic entity with potential treatment target?

Abstract

Myeloid and lymphoid neoplasms resulting from t(8;9)(p21-23;p23-24) involving pericentriolar material 1 (PCM1) gene and the janus-activated kinase 2 (JAK2) gene are very rare disorders. Most patients present with myeloproliferative neoplasms (MPN) or myelodysplastic/myeloproliferative neoplasms (MDS-MPN) accompanied by eosinophilia and myelofibrosis. Their clinical course is more aggressive than other MPN and MDS-MPN with tendency to transformation to acute myeloid leukemia. Translocation t(8;9)(p22;p24) with PCM1-JAK2 fusion leads to constitutive activation of JAK2. Such patients might be candidates for target therapies with JAK2 inhibitors. We report a patient with chronic eosinophilic leukemia, not otherwise specified with erythroblastic proliferation of unclear significance and the translocation (8;9) (p22;p24) with PCM1-JAK2 fusion gene. The presence of characteristic genetic aberration with potential terapeutic target tends to separate this disease as a distinct clinical, histopathological and genetic entity.
Hematologia 2011; 2, 4: 370–377