Juvenile Myelomonocytic Leukemia in China: a Retrospective Analysis of 63 Cases

Objective: To define the status of juvenile myelomonocytic leukemia(JMML) patients in China, in terms of clinical characteristics, gene mutations, clinical course and treatment strategies. Materials and Methods: We retrospectively analysed the data of clinical and laboratory from our department in China. Including clinical characteristics, gene mutational studies and treatment strategies.Results: 63 cases of patients with JMML from Jan 2008 to Oct 2016 were enrolled into the study. The median age at diagnosis was 25 months (range 2-72 months). All patients presented splenomegaly at the diagnosis. Abnormal blood routine test and fever were the most common complain at the diagnosis. Heptosplenomegaly was the common sign. The median WBC, monocyte and platelet counts were 32.3×10⁹/L, 5.1×10⁹/L, 75.6×10⁹/L. Monosomy 7 was present in 8.5% of patients. JMML mutations analysis was performed in 56 out of 63 patients (88.9%). PTPN11 was the most common mutation accounting for 41.1%. Ras, NF1, CBL mutations were 39.3%, 3.6%, 1.8%. Only ten of 63 patients(15.9%) underwent hematopoietic stem cell transplantation(HSCT), and 6 patients died(disease related, n=1, transplantation-related complications, n=3, infection, n=2). The 5-year overall survival(OS) rate was 33.4±7.9%. In HSCT group the 5-year OS was 42.0±17.6%. We have done the univariate analysis, hepatosplenomegaly, the number of platelet lower than 40 ×10⁹/l, PTPN11 mutation were the poor prognosis factors. Conclusions: Although there has been improvement in the diagnosis and treatment in JMML in China. The overall results are not satisfactory and it is necessary to put more effort into the definitive diagnosis and HSCT.