Coexistence of breakpoint cluster region-Abelson1 rearrangement and Janus kinase 2 V617F mutation in chronic myeloid leukemia: A case report

BACKGROUND The Janus kinase 2(JAK2) V617 F mutation is common in patients with breakpoint cluster region-Abelson1(BCR-ABL1)-negative myeloproliferative neoplasms,including polycythemia vera, essential thrombocythemia and primary myelofibrosis, but is rarely detected in BCR-ABL1-positive chronic myeloid leukemia(CML) patients. Here, we report a CML patient with both a BCR-ABL1 rearrangement and JAK2 V617 F mutation.CASE SUMMARY A 45-year-old Chinese woman was admitted to our department with a history of significant thrombocytosis for 20 d. Color Doppler ultrasound examination showed mild splenomegaly. Bone marrow aspiration revealed a karyotype of 46,XX, t(9;22)(q34;q11.2) in 20/20 metaphases by cytogenetic analysis,rearrangement of BCR-ABL1(32.31%) by fluorescent polymerase chain reaction(PCR) and mutation of JAK2 V617 F(10%) by PCR and Sanger DNA sequencing.The patient was diagnosed with CML and JAK2 V617 F mutation. Following treatment with imatinib for 3 mo, the patient had an optimal response and BCRABL1(IS) was 0.143%, while the mutation rate of JAK2 V617 F rose to 15%.CONCLUSION Emphasis should be placed on the detection of JAK2 mutation when CML is diagnosed to distinguish JAK2 mutation-positive CML and formulate treatment strategies.