Juvenile myelomonocytic leukemia (JMML) is a disorder characterized by the simultaneous presence of myeloproliferative and myelodysplastic features, primarily affecting infants and young children. Due to the heterogeneous genetic background among patients, the current clinical and laboratory prognostic features are insufficient for accurately predicting outcomes. Thus, there is a pressing need to identify novel prognostic indicators. Red cell distribution width (RDW) is a critical parameter reflecting the variability in erythrocyte size. Recent studies have emphasized that elevated RDW serves as a valuable predictive marker for unfavorable outcomes across various diseases. However, the prognostic role of RDW in JMML remains unclear. Patients with JMML from our single-center cohort between January 2008 and December 2019 were included. Overall, 77 patients were eligible. Multivariate Cox proportional hazard models showed that patients with red cell distribution width coefficient of variation (RDW-CV) >17.35% at diagnosis were susceptible to much worse overall survival rate (hazard ratio [HR] = 5.22, confidence interval [CI] = 1.50-18.21, P = .010). Besides, the combination of RDW elevation and protein phosphatase non-receptor type 11 (PTPN11) mutation was likely to predict a subgroup with the worst outcomes in our cohort. RDW is an independent prognostic variable in JMML subjects. RDW may be regarded as an inexpensive biomarker to predict the clinical outcome in patients with JMML.

Behçet\'s disease (BD) is a rare condition that is seldom associated with hematological malignancies. In this case report, we present the unique case of a 7-year-old girl diagnosed with juvenile myelomonocytic leukemia (JMML) and intestinal BD. The patient received allogeneic hematopoietic stem cell transplantation (allo-HSCT), which resulted in complete remission of both JMML and BD. Our findings suggest that allo-HSCT may be a feasible treatment option for JMML patients with coexisting BD, and holds promise for achieving remission of both illnesses. However, further clinical investigations are needed to validate these findings.

OBJECTIVE: 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.
目的: 探讨幼年型粒单核细胞白血病（juvenile myelomonocytic leukemia，JMML）的临床特征与预后之间的关系。方法: 收集2008年1月—2016年12月收治的JMML患儿临床资料及预后，分析影响JMML患儿预后的因素。结果: 共纳入63例JMML患儿，中位发病年龄为25个月，男女性别3.2∶1。54例患儿完成JMML基因检测，PTPN11基因突变最常见（23例，43%），其中单纯PTPN11基因突变19例，伴PTPN11基因复合突变4例；其次为NRAS基因突变（14例，26%），其中单纯NRAS基因突变12例，包含NRAS基因复合突变2例。5年总生存（overall survival，OS）率仅为22%±10%。13例（21%）患儿进行造血干细胞移植（hematopoietic stem cell transplantation，HSCT）。HSCT组患儿5年OS率高于非HSCT组患儿（46%±14% vs 29%±7%，P<0.05）。无PTPN11基因突变与PTPN11基因突变患儿5年OS率比较差异无统计学意义（30%±14% vs 27%±10%，P>0.05）。Cox比例风险回归模型分析显示，初诊血小板计数<40×109/L是影响JMML患儿5年OS率的因素（P<0.05）。结论: PTPN11基因是JMML最常见的突变基因。初诊血小板计数与JMML患儿预后有关。HSCT可改善JMML患儿预后。.

Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric myeloproliferative disease, and newly diagnosed patients frequently cannot tolerate hematopoietic stem cell transplantation (HSCT) at diagnosis due to their poor condition. This retrospective analysis aimed to explore the short-term effect of decitabine-dominant therapy on improving the condition of JMML patients before HSCT. The subjects were 10 JMML patients. All patients were treated with decitabine after low-dose chemotherapy with an interval of 4 weeks before bridging to HSCT. The median treatment course was 3 cycles, and the overall response rate (ORR) was 70.0% after one cycle and 71.4% after three cycles. White blood cell (WBC) and monocyte counts were significantly lower after treatment, and spleen volume was also lower, though not significantly lower. The 12 month progression-free survival rate (PFS) was 80.0 ± 12.6%. Decitabine-dominant therapy was beneficial for reducing tumor burden and improving clinical condition.

BACKGROUND: Juvenile myelomonocytic leukemia (JMML) is a rare hematological malignancy in young children and can only be cured through the allogeneic stem cell transplantation.
METHODS: We have retrospectively analyzed the outcomes of nine children with JMML after unrelated cord blood transplantation (UCBT).
RESULTS: Eight patients who have received a myeloablative conditioning regimen of fludarabine (FLU), busulfan (BU), and cyclophosphamide (CY) have gotten engraftment. None of the nine patients has relapsed following initial UCBT. Six patients are still alive and in complete remission after UCBT with a median observation time of 43 months (range: 10-80 months).
CONCLUSIONS: This study shows that UCBT with FLU-BU-CY conditioning regimen can represent a suitable option for children with JMML.

Juvenile myelomonocytic leukemia (JMML) is a heterogeneous childhood leukemia. The management of patients with JMML requires accurate assessment of genetic and clinical features to help in patient risk stratification. This study aimed to investigate the association between genomic alterations and prognosis in children with JMML. Genomic DNA was extracted from a total of 93 patients with JMML for targeted sequencing. Univariable and multivariable analysis were used to evaluate the correlation between gene mutations and prognosis of the patients. Patients with PTPN11 mutation exhibited significantly lower event-free survival (EFS) compared with non-PTPN11 mutations (P = 0.005). Patients without or with one somatic alteration at diagnosis showed significantly better prognosis in comparison with those with more than two alterations (P = 0.009). PTPN11 mutation with additional alterations showed significantly the poorest outcome in comparison with those with only one non-PTPN11 mutation, only one PTPN11 mutation, and combined mutations without PTPN11, respectively (P < 0.0001).Conclusion: Both PTPN11 mutation and the number of somatic alterations detected at diagnosis are likely to be the major determinant of outcome in JMML. The subgroup of patients with PTPN11 mutation showed the shortest survival which was even worsened when a secondary mutation was present.

Objective: To investigate clinical features, diagnosis, treatment strategies and prognosis of juvenile myelomonocytic leukemia (JMML). Methods: The clinical data of 21 patients with JMML who were diagnosed in our hospital from January 2013 to May 2018 were retrospectively analyzed. Results: Among the 21 children with JMML, 16 were male and 5 were female. Out of the 21 children who were diagnosed with JMML, 7 were lost after treatment while the remaining 14 received A-3V chemotherapy regimen of South Korea. The effective response rate was 78.5%. The three-year overall survival (OS) rate and three-year disease-free survival (DFS) rate were (76.2 ± 14.8)% and (66.2 ± 14)%, respectively. Single factor analysis showed that PLT count ≤33×109/L, LDH level >500 U/L and HbF level >10% and chemotherapy only were the significant factors that lead to poor prognosis in children. Cox multivariate analysis showed that the choice of treatment options affected the prognosis of JMML children. By taking prognostic factors for long-term efficacy into account, patients with treatment strategy of chemotherapy alongside hematopoietic stem cell transplantation (HSCT) have a better prognosis. Conclusion: The PLT count, LDH level, HbF level and choice of treatment plan are important for the evaluation of prognosis for children with JMML. Although there is a lack of consistency in terms of donors but the A-3V scheme is relatively stable, so HSCT should be preferred for children with poor prognostic factors.

BACKGROUND: The proto-oncogene KRAS performs an essential function in normal tissue signaling, and the mutation of KRAS gene is a key step in the development of many cancers. Somatic KRAS mutations are often detected in patients with solid and non-solid tumors, whereas germline KRAS mutations are implicated in patients with the Noonan syndrome, cardio-facio-cutaneous (CFC) syndrome and Costello syndrome. The deletion of chromosome 10q22.3-q23.2 is a rare cytogenetic abnormality, which often leads to distinct facial appearance and delays in speech and global development.
METHODS: Herein, we report the case of a 4-year-old boy diagnosed with juvenile myelomonocytic leukemia. The boy also had syndromic features, such as speech and motor developmental delay, multiple congenital malformations, including distinct facial features, club feet, and cryptorchidism. Using whole-exome sequencing, we identified a pathogenic mutation in KRAS [c.34G > A, p.Gly12Ser] isolated from peripheral blood DNA. Sanger sequencing confirmed the wild-type sequence in the parents and patient\'s salivary cell DNA indicating its somatic state. A 7311-kb deletion in 10q22.3-q23.2 was also revealed by chromosomal microarray analysis, which was later proved as a germline de novo variant.
CONCLUSIONS: Juvenile myelomonocytic leukemia in the patient was attributed to a somatic KRAS mutation, whereas the syndromic features of the patient were considered a consequence of germline chromosome 10q22.3-q23.2 deletion. Genetic testing for patients with complicated phenotypes can be valuable in detecting multiple pathogenic variants.