JAK2 V617F Mutation In Atypical Chronic Myeloid Leukemia

Abstract 5069

Atypical chronic myeloid leukemia (aCML) is a rare leukemic disorder which shows myelodysplastic and myeloproliferative features simultaneously. Some cases of JAK2 V617F mutation in aCML were reported before WHO criteria introduced (Jelinek J et al. Blood 2005; Jones AV et al. Blood 2005; Levine RL et al. Blood 2005). However, Fend F et al observed no JAK2 V617F mutation in aCML as defined by WHO classification (Fend F et al. Leuk Res 2008), which result was refuted by a case report (Campiotti L et al. Leuk Res 2009). Here we analyzed JAK2 V617F mutation with amplification refractory mutation system (ARMS) and direct sequencing in three cases of aCML and found a case with JAK2 V617F mutation. All three cases were diagnosed as aCML according to WHO classification and showed significant myelodysplastic/myeloproliferative features in peripheral blood and bone marrow aspirates. Absence of BCR/ABL1 gene rearrangement was confirmed by FISH analysis, and conventional cytogenetic analysis revealed trisomy 8 in a case with no JAK2 V617F mutation. The patient with JAK2 V617F mutation poorly responds with hydroxyurea therapy and is showing prolonged leukocytosis.