[Analysis of Essential Thrombocythemia to Acute Myeloid Leukemia]

To improve the understanding of the transformation of essential thrombocythemia (ET) into acute myeloid leukemia (AML), and to explore the relationship between JAK2 V617F gene mutation and disease transformation.

The detection of bone marrow morphology,cytogenetics, JAK2 V617F gene were performed before and after transformation, as well as the immunological tests after transformation was performed in 3 patients with ET into AML. The characteristics, clinical features, diagnosis and treatment of the patients before and after transformation were compared.

Case 1 transformed into AML-M2a 5 years after diagnosis of ET. The patient abandoned treatment and was discharged from hospital. Case 2 transformed into AML 6 years after diagnosis of ET. After one course of chemotherapy, bone marrow was partially relieved, and platelets continued to rise up to 702×10⁹/L, presenting as ET bone marrow image. One year later, AML relapsed and no remission was observed after chemotherapy. Case 3 transformed into AML-M6a 7 years after diagnosis of ET. The patient abandoned treatment and was discharged from hospital. The morphological heteromorphism of 3 cases of AML transformed from ET was more obvious than that of patients with newly diagnosed acute leukemia. The AML could not be classified accurately based on morphology simply, but could be classified accurately based on immunological detection. JAK2 V617F gene was positive before and after transformation in case 1 and case 2 of ET, the case 3 showed that JAK2 V617F gene was positive at ET stage and negative after AML transformation. Complex chromosome karyotypes were detected by routine karyotype analysis after ET transformation into AML in case 1, while normal karyotypes were found in case 2 and case 3.

The morphological abnormality of AML transformed from ET is more significant than that of newly diagnosed acute leukemia, and it needs immunological detection to classify it accurately. The transformation of ET into AML may not involve JAK2 V617F gene mutation, but may be related with the occurrence of abnormal chromosome karyotypes. The condition of AML transformed from ET is dangerous and the effect of chemotherapy is poor.