OBJECTIVES: To investigate the genomic characteristics and prognostic factors of juvenile myelomonocytic leukemia (JMML) with RAS mutations. METHODS: A retrospective analysis was conducted on the clinical data of JMML children with RAS mutations treated at the Hematology Hospital of Chinese Academy of Medical Sciences, from January 2008 to November 2022. RESULTS: A total of 34 children were included, with 17 cases (50%) having isolated NRAS mutations, 9 cases (27%) having isolated KRAS mutations, and 8 cases (24%) having compound mutations. Compared to children with isolated NRAS mutations, those with NRAS compound mutations showed statistically significant differences in age at onset, platelet count, and fetal hemoglobin proportion (P<0.05). Cox proportional hazards regression model analysis revealed that hematopoietic stem cell transplantation (HSCT) and hepatomegaly (≥2 cm below the costal margin) were factors affecting the survival rate of JMML children with RAS mutations (P<0.05); hepatomegaly was a factor affecting survival in the non-HSCT group (P<0.05). CONCLUSIONS Children with NRAS compound mutations have a later onset age compared to those with isolated NRAS mutations. At initial diagnosis, children with NRAS compound mutations have poorer peripheral platelet and fetal hemoglobin levels than those with isolated NRAS mutations. Liver size at initial diagnosis is related to the prognosis of JMML children with RAS mutations. HSCT can improve the prognosis of JMML children with RAS mutations.
Humans ; Leukemia, Myelomonocytic, Juvenile/therapy* ; Mutation ; Male ; Female ; Child, Preschool ; Retrospective Studies ; Child ; Infant ; GTP Phosphohydrolases/genetics* ; Membrane Proteins/genetics* ; Adolescent ; Hematopoietic Stem Cell Transplantation ; Proportional Hazards Models ; Proto-Oncogene Proteins p21(ras)/genetics* ; Prognosis

Objective: To investigate the genetic and genomic profiling of juvenile myelomonocytic leukemia (JMML) and factors affecting its survival rate. Methods: Clinical characteristics, cytogenetics, molecular biology results and survival status of children with 27 JMML cases admitted to the Hematology Department of Children's Hospital, Capital Institute of Pediatrics from December 2012 to December 2021 were analyzed retrospectively, and the outcomes of the children were followed up. Kaplan-Meier method was used for survival analysis. Univariate analysis was used for analyzing factors affecting the overall survival (OS) rates of patients who received hematopoietic stem cell transplantation (HSCT). Log-Rank test was used for comparison of survival curves. Results: Among 27 JMML cases, there were 11 males and 16 females. The age of disease onset was 28 (11,52) months. There are 20 cases of normal karyotype, 4 cases of monosomy 7, 1 case of trisomy 8,1 case of 11q23 rearrangement and 1 case of complex karyotype. A total of 39 somatic mutations were detected.Those involved in RAS signal pathway were the highest (64%(25/39)), among which PTPN11 mutation was the most frequent (44% (11/25)). A total of 17 cases (63%) received HSCT, 8 cases (30%) did not receive HSCT, and 2 cases (7%) lost follow-up. For children receiving transplantation, the follow-up time after transplantation was 47 (11,57) months. The 1-year OS rate of high-risk transplantation group (17 cases) and high-risk non transplantation group (6 cases) was (88±8)% and (50±20)% respectively, with a statistically significant difference (χ²=5.01, P=0.025). The 5-year OS rate of the high-risk transplantation group was (75±11)%. The survival time of those who relapsed or progressed to acute myeloid leukemia after transplantation was significantly shorter than that of those who did not relapse (χ²=6.80, P=0.009). The OS rate of patients with or without PTPN11 mutation was (81±12) % and (67±19)% respectively (χ²=0.85, P=0.356). Conclusions: The main pathogenesis involved in JMML is gene mutation related to RAS signaling pathway, and the most common driver gene of mutation is PTPN11. Allogeneic HSCT can significantly improve the survival rate of high-risk JMML patients. The recurrence or progression after transplantation was related to poor prognosis.
Male ; Female ; Child ; Humans ; Child, Preschool ; Leukemia, Myelomonocytic, Juvenile/therapy* ; Retrospective Studies ; Survival Analysis ; Mutation ; Hematopoietic Stem Cell Transplantation

OBJECTIVES: To investigate the clinical features of juvenile myelomonocytic leukemia (JMML) and their association with prognosis. METHODS: Clinical and prognosis data were collected from the children with JMML who were admitted from January 2008 to December 2016, and the influencing factors for prognosis were analyzed. RESULTS: A total of 63 children with JMML were included, with a median age of onset of 25 months and a male/female ratio of 3.2∶1. JMML genetic testing was performed for 54 children, and PTPN11 mutation was the most common mutation and was observed in 23 children (43%), among whom 19 had PTPN11 mutation alone and 4 had compound PTPN11 mutation, followed by NRAS mutation observed in 14 children (26%), among whom 12 had NRAS mutation alone and 2 had compound NRAS mutation. The 5-year overall survival (OS) rate was only 22%±10% in these children with JMML. Of the 63 children, 13 (21%) underwent hematopoietic stem cell transplantation (HSCT). The HSCT group had a significantly higher 5-year OS rate than the non-HSCT group (46%±14% vs 29%±7%, P<0.05). There was no significant difference in the 5-year OS rate between the children without PTPN11 gene mutation and those with PTPN11 gene mutation (30%±14% vs 27%±10%, P>0.05). The Cox proportional-hazards regression model analysis showed that platelet count <40×10⁹/L at diagnosis was an influencing factor for 5-year OS rate in children with JMML (P<0.05). CONCLUSIONS The PTPN11 gene was the most common mutant gene in JMML. Platelet count at diagnosis is associated with the prognosis in children with JMML. HSCT can improve the prognosis of children with JMML.
Child ; Humans ; Male ; Female ; Child, Preschool ; Leukemia, Myelomonocytic, Juvenile/therapy* ; Prognosis ; Genetic Testing ; Mutation ; Hematopoietic Stem Cell Transplantation

Humans ; Leukemia, Myelomonocytic, Juvenile/therapy*

A 1.1 year old boy was admitted to the Seoul National University Children's Hospital because of incidental findings of hepatosplenomegaly, skin lesion and multiple intra- abdominal lymphadenopathies. Anemia and thrombocytopenia were found based on the initial complete blood count (CBC) measurements. Because of bicytopenia and hepatosplenomegaly, bone marrow examination was performed which revealed hypercellular marrow with increased monocytes and granulopoiesis. The hemoglobin F level was high for his age, and monocyte production was increased. The patient was diagnosed with juvenile myelomonocytic leukemia at the age of 1.2 years. Chemotherapy with cytarabine, etoposide, vincristine, and isotretinoin was initiated. After 6 cycles of chemotherapy, the CBC normalized. He underwent double cord blood transplantation (dCBT), but chimerism studies showed autologous recovery. However, he did not show relapse during the 5 years post-transplant during which he received isotretinoin. He is surviving disease-free 9 years after dCBT.
Anemia ; Blood Cell Count ; Bone Marrow ; Bone Marrow Examination ; Chimerism ; Cytarabine ; Drug Therapy ; Etoposide ; Fetal Blood ; Fetal Hemoglobin ; Humans ; Incidental Findings ; Isotretinoin ; Leukemia, Myelomonocytic, Juvenile ; Male ; Monocytes ; Recurrence ; Seoul ; Skin ; Thrombocytopenia ; Vincristine

This study was purposed to explore the therapeutic efficacy and influencing factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with chronic myelomonocytic leukemia (CMML) and in patients with juvenile myelomonocytic leukemia (JMML). The clinical data of 3 cases of CMML and 2 cases of JMML underwent allo-HSCT were analysed in term of multiparameter. The results showed that the hematopoietic stem cells in 5 patients grafted successfully. One case of JMML died of pulmonary disease, other 4 cases survive without disease. The analysis found that the disease burden before transplant, chromosome karyotype, acute GVHD II-IV and poor risk cytogenetics all associated with the relapse rate and disease-free survival rate of CMML. The low intensity conditioning regimen was better than myeloablative conditioning regimen. Type of donor and source of stem cells did not statistically and significantly affect OS and RFS. The splenectomy before allo-HSCT as well as spleen size at time of the alloHSCT did not influence on posttransplantation outcome of JMML. However, cord blood HSCT for JMML patients delayed hematologic recovery as compared to that of bone marrow or peripheral blood HSCT. The age, GVHD, HbF level played an important role in leukemia replace. It is concluded that the allogeneic hematopoietic stem cell transplantation is a curative regimen for CMML and JMML, but there also is a serial problems to be resolved.
Adult ; Child, Preschool ; Hematopoietic Stem Cell Transplantation ; Humans ; Infant ; Leukemia, Myelomonocytic, Chronic ; therapy ; Leukemia, Myelomonocytic, Juvenile ; therapy ; Male ; Middle Aged ; Transplantation, Homologous ; Treatment Outcome

PURPOSE: The purpose of this study was to evaluate the outcome of children with juvenile myelomonocytic leukemia(JMML) treated with allogeneic hematopoietic stem cell transplantation(allo- HSCT). METHODS: Eleven JMML patients aged 8-39 months underwent allo-HSCT. The sources of grafts were unrelated donors(n=7), HLA-matched siblings(n=3) and an HLA 1-antigen mismatched familial donor. All patients had received chemotherapy +/- 13-cis-retinoic acid(CRA) before transplant, and CRA was used, posttransplant, in six patients. RESULTS: Only three patients were in complete remission(CR) at the time of transplantation. Initial chimeric status revealed complete donor chimerism(CC) in five patients, mixed chimerism(MC) in five and autologous recovery(AR) in one. One patient with MC having persistent splenomegaly eventually turned to CC and CR after rapid tapering of cyclosporine, combined with daily use of CRA. An AR case relapsed shortly after transplant but was rescued with second, unrelated cord blood transplantation. Ultimately, six patients are alive, event-free, with a median follow-up of 15.5 months posttransplant. All three deaths occurred in patients who failed to achieve CC, leading to disease progression. CONCLUSION: We suggest that graft-versus-leukemia effect play an important role and CRA a possible role in posttransplant leukemic involution in JMML. In patients whose leukemic burden is still high with MC after transplant, early tapering of immunosuppressants and introduction of CRA might provide a chance of a cure for some patients.
Child ; Cyclosporine ; Disease Progression ; Drug Therapy ; Fetal Blood ; Follow-Up Studies ; Hematopoietic Stem Cell Transplantation* ; Hematopoietic Stem Cells* ; Humans ; Immunosuppressive Agents ; Isotretinoin ; Leukemia* ; Leukemia, Myelomonocytic, Juvenile ; Splenomegaly ; Tissue Donors ; Transplants