Allogeneic hematopoietic stem cell transplantation for pediatric acute lymphoblastic leukemia.

This study was aimed to explore the prognosis of allogenic hematopoietic stem cell transplantation (allo-HSCT) in pediatric patients with acute lymphoblastic leukemia (ALL). This retrospective case series study included children with ALL who underwent allo-HSCT at Beijing Children's Hospital of Capital Medical University, Beijing, China, between January 2009 and December 2019. The outcomes included 5-year overall survival (OS) and event-free survival (EFS). A total of 75 children (52 males) were included. The median age at presentation was 5.30 years, and the median time from diagnosis to transplantation was 1.64 years. There were 15 human leukocyte antigen (HLA)-matched and 60 HLA-semi-matched transplants, 73 complete remissions (CR), and 2 MRD-positive transplants. The median follow-up time was 41 months. Out of 75 patients, 51 children survived, and 24 died/given up at the terminal stage. The 5-year OS and EFS rates were 67.77% and 57.30%, respectively, whereas the 5-year recurrence rate was 35.69%. Acute and chronic graft versus host diseases occurred in 40 and 28 cases, respectively. Children with MLL gene fusion had higher survival rates compared to other subgroups. Haplo-HSCT is not inferior to HLA-matched transplant. The children with MLL rearrangement had an acceptable 5-year OS, while complications and relapse should be monitored.

Optimal dosage of rituximab for children with Burkitt lymphoma.

The current chemotherapy treatments have led to an improvement in survival rates for pediatric Burkitt's lymphoma (BL). Survival in children with high-grade, mature B-cell non-Hodgkin's lymphoma (B-NHL) has been prolonged by six rituximab doses combined with chemotherapy, whereas the efficacy of four doses has not been reported. This study aimed to explore optimal therapeutic strategies-the number of doses of rituximab based on different risk groups-and also aim to investigate the clinical characteristics of Chinese pediatric BL. This study consecutively enrolled children with BL in Beijing Children's Hospital who received French-American-British mature B-cell lymphoma 96 (FAB/LMB96). The patients were divided into three groups: R0 group (chemotherapy alone), R6 group (chemotherapy combined with six rituximab doses), and R4 group (chemotherapy combined with four rituximab doses). The clinical characteristics and outcomes were evaluated. Univariate and multivariate analyses and prognostic nomogram were used to assess prognostic factors. A nomogram was developed that predicted overall survival based on the Cox proportional hazards model, and the concordance index (C-index) and a calibration curve were used to determine its predictive and discriminatory capacity. We enrolled 385 boys and 71 girls, with a median age of 6 years (1-14 years). Of these, 296 patients (65%) had initial abdominal symptoms, 182 (40%) had bulky disease, 46 (10%) had B symptoms, 77 (16.9%) had BL-ALL (blasts ≥ 25% in bone marrow (BM)), 96 (21%) had central nervous system (CNS) disease, 406 (89%) were in stages III-IV, 378 (83%) were in group C, 170 (37.2%) had lactate dehydrogenase (LDH) levels ≥ 1000 U/L at initial diagnosis, and 137 (30%) had tumor lysis syndrome. The R0, R6, and R4 groups included 79, 144, and 227 patients, respectively. Six patients were excluded due to treatment withdrawal for various reasons. The 3-year overall survival (OS) and event-free survival (EFS) percentages were 92% ± 1.3% and 91.3% ± 1.3%, respectively, in all cohorts, whereas the 3-year EFS percentage was 83.5% ± 4.2%, 93% ± 2.1%, and 92.9% ± 1.8% in the R0, R6, and R4 groups, respectively (P = 0.025). The nomogram included four important variables based on a multivariate analysis of the primary cohort: course of disease ≤ 20 days, presence of bulky disease at the beginning of diagnosis, central nervous system(CNS) invasion, and dosage of rituximab. The calibration curve showed that the nomogram was able to predict 3-year OS accurately. The C-index of the nomogram for OS prediction was 0.79 for both cohorts. In our hospital, pediatric BL was more commonly observed in school-age boys with an abdominal mass and mostly in advanced stages at initial diagnosis. The FAB/LMB96 regimen combined with rituximab significantly increased survival outcomes. We observed no significant differences between four and six doses of rituximab in terms of treatment outcomes. The proposed nomogram provides an individualized risk estimate of OS in patients with BL and may assist treatment decision-making or rituximab dose design.

Clinical characteristics of SARS-CoV-2 Omicron variant infection in children with acute leukemia.

Hematologic diseases and various therapeutic stages can impact the presentation of SARS-CoV-2 Omicron variant infection. This study retrospectively analyzed data on Omicron infection in children with acute leukemia treated at our hospital between January 16, 2023, and February 25, 2023, using questionnaires. The prevalence of Omicron infection in children undergoing consolidation chemotherapy, maintenance chemotherapy, drug withdrawal, and healthy children was 81.8%, 75.2%, 55.2%, and 61.9%, respectively. The observed differences were statistically significant (P < 0.05). During the course of infection, children with leukemia undergoing chemotherapy, including both the consolidation and maintenance chemotherapy groups, exhibited a prolonged time to achieve SARS-CoV-2 negativity compared to the drug withdrawal and healthy groups. However, there was no significant increase in the incidence of symptoms across all body systems, and no children experienced serious sequelae or death. Furthermore, our observations indicated that all manifestations of Omicron infection in children with leukemia after drug withdrawal were not significantly different from those in healthy children. This suggested, to a certain extent, that the immune function of children with leukemia recovers effectively after the cessation of drug treatment. These findings are crucial for guiding clinical management and alleviating concerns about infection for both children with leukemia and their parents.

Longitudinal changes in body mass index, height, and weight in children with acute myeloid leukemia.

BACKGROUND: This study reported height prediction and longitudinal growth changes in Chinese pediatric patients with acute myeloid leukemia (AML) during and after treatment and their associations with outcomes. METHODS: Changes in 88 children with AML in percentages according to the growth percentile curve for Chinese boys/girls aged 2-18/0-2 years for body mass index (BMI), height, and weight from the time of diagnosis to 2 years off therapy were evaluated. The outcomes of AML were compared among patients with different BMI levels. RESULTS: The proportion of underweight children (weight < 5th percentile) increased significantly from the initial diagnosis to the end of consolidation treatment. The proportion of patients with low BMI (BMI < 5th percentile) was highest (23.08%) during the consolidation phase, and no children were underweight, but 20% were overweight (BMI > 75th percentile) after 2 years of drug withdrawal. Unhealthy BMI at the initial diagnosis and during intensive chemotherapy leads to poorer outcomes. For height, all patients were in the range of genetic height predicted based on their parents' height at final follow-up. CONCLUSIONS: Physicians should pay more attention to the changes in height and weight of children with AML at these crucial treatment stages and intervene in time.

Socioeconomic inequalities in cancer incidence and access to health services among children and adolescents in China: a cross-sectional study.

BACKGROUND: Despite the substantial burden caused by childhood cancer globally, childhood cancer incidence obtained in a nationwide childhood cancer registry and the accessibility of relevant health services are still unknown in China. We comprehensively assessed the most up-to-date cancer incidence in Chinese children and adolescents, nationally, regionally, and in specific population subgroups, and also examined the association between cancer incidence and socioeconomic inequality in access to health services. METHODS: In this national cross-sectional study, we used data from the National Center for Pediatric Cancer Surveillance, the nationwide Hospital Quality Monitoring System, and public databases to cover 31 provinces, autonomous regions, and municipalities in mainland China. We estimated the incidence of cancer among children (aged 0-14 years) and adolescents (aged 15-19 years) in China through stratified proportional estimation. We classified regions by socioeconomic status using the human development index (HDI). Incidence rates of 12 main groups, 47 subgroups, and 81 subtypes of cancer were reported and compared by sex, age, and socioeconomic status, according to the third edition of the International Classification of Childhood Cancer. We also quantified the geographical and population density of paediatric oncologists, pathology workforce, diagnoses and treatment institutions of paediatric cancer, and paediatric beds. We used the Gini coefficient to assess equality in access to these four health service indicators. We also calculated the proportions of cross-regional patients among new cases in our surveillance system. FINDINGS: We estimated the incidence of cancer among children (aged 0-14 years) and adolescents (aged 15-19 years) in China from Jan 1, 2018, to Dec 31, 2020. An estimated 121 145 cancer cases were diagnosed among children and adolescents in China between 2018 and 2020, with world standard age-standardised incidence rates of 122·86 (95% CI 121·70-124·02) per million for children and 137·64 (136·08-139·20) per million for adolescents. Boys had a higher incidence rate of childhood cancer (133·18 for boys vs 111·21 for girls per million) but a lower incidence of adolescent cancer (133·92 for boys vs 141·79 for girls per million) than girls. Leukaemias (42·33 per million) were the most common cancer group in children, whereas malignant epithelial tumours and melanomas (30·39 per million) surpassed leukaemias (30·08 per million) in adolescents as the cancer with the highest incidence. The overall incidence rates ranged from 101·60 (100·67-102·51) per million in very low HDI regions to 138·21 (137·14-139·29) per million in high HDI regions, indicating a significant positive association between the incidence of childhood and adolescent cancer and regional socioeconomic status (p<0·0001). The incidence in girls showed larger variation (48·45% from the lowest to the highest) than boys (36·71% from lowest to highest) in different socioeconomic regions. The population and geographical densities of most health services also showed a significant positive correlation with HDI levels. In particular, the geographical density distribution (Gini coefficients of 0·32-0·47) had higher inequalities than population density distribution (Gini coefficients of 0·05-0·19). The overall proportion of cross-regional patients of childhood and adolescent cancer was 22·16%, and the highest proportion occurred in retinoblastoma (56·54%) and in low HDI regions (35·14%). INTERPRETATION: Our study showed that the burden of cancer in children and adolescents in China is much higher than previously nationally reported from 2000 to 2015. The distribution of the accessibility of health services, as a social determinant of health, might have a notable role in the socioeconomic inequalities in cancer incidence among Chinese children and adolescents. With regards to achieving the Sustainable Development Goals, policy approaches should prioritise increasing the accessibility of health services for early diagnosis to improve outcomes and subsequently reduce disease burdens, as well as narrowing the socioeconomic inequalities of childhood and adolescent cancer. FUNDING: National Major Science and Technology Projects of China, National Natural Science Foundation of China, Chinese Academy of Engineering Consulting Research Project, Wu Jieping Medical Foundation, Beijing Municipal Administration of Hospitals Incubating Program.

Clinical Significance of Plasma Soluble MICB in Children With EBV-associated Hemophagocytic Lymphohistiocytosis.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal systemic inflammation disease in children. The most common cause is Epstein-Barr virus (EBV) infection. MHC class I polypeptide-related sequence B (MICB) is a membrane protein inducibly expressed upon cellular stress, viral infection, or malignant transformation, thus marking these cells for clearance through natural killer group 2 member D-positive lymphocytes. MICB can be released into plasma through several mechanisms, reducing NK cell cytotoxicity. METHODS: We conducted clinical research on HLH patients and cell research in vitro. In the retrospective clinical part, 112 HLH patients (including EBV-HLH group and non-EBV-HLH group), 7 infectious mononucleosis patients, and 7 chronic active EBV infection patients were treated in Beijing Children's Hospital, affiliated with Capital Medical University, from January 2014 to December 2020, were enrolled in this study. Real-time quantitative polymerase chain reaction, standard enzyme-linked immunosorbent assay methods, and lactate dehydrogenase release tests were used to examine the expression of MICB mRNA, the soluble MICB (sMICB) levels, and the activity of NK cells in those patients. In vitro research, MICB overexpression-vector virus, MICB knockdown-vector virus, and empty-vector virus were transfected into two kinds of target cells, such as K562 and MCF7. The level of sMICB and NK cell killing activity between other groups was compared. Finally, we compared NK92 cell killing activity in different concentrations of sMICB. RESULTS: In clinical studies, compared with the non-EBV-HLH group, the EBV-HLH group had lower NK cell killing activity ( P < 0.05). The level of sMICB in the EBV-HLH group was significantly higher than in non-EBV-HLH, infectious mononucleosis, and chronic active EBV infection patients ( P ＜0.05). A high level of sMICB was associated with poor treatment response and poor prognosis ( P ＜0. 05). Cellular studies showed that an increased level of membrane MICB could positively correlate with the killing activity of NK92 cells ( P ＜0. 05), and a high level of sMICB (1250 to 5000pg/ml) could reduce the killing activity of NK92 cells ( P < 0.05). A high level of sMICB (2500pg/ml) could increase the release of cytokines from NK92 cells. CONCLUSION: The expression level of sMICB in EBV-HLH patients increased, and a high level of sMICB at the initial onset indicated a poor treatment response. The killing activity of NK cells in EBV-HLH patients decreased more significantly. The high level of sMICB may inhibit the killing activity but increase the release of cytokines of NK92 cells.

Transduction of modified factor VIII gene improves lentiviral gene therapy efficacy for hemophilia A.

Hemophilia A (HA) is a bleeding disorder caused by deficiency of the coagulation factor VIII (F8). F8 replacement is standard of care, whereas gene therapy (F8 gene) for HA is an attractive investigational approach. However, the large size of the F8 gene and the immunogenicity of the product present challenges in development of the F8 gene therapy. To resolve these problems, we synthesized a shortened F8 gene (F8-BDD) and cloned it into a lentiviral vector (LV). The F8-BDD produced mainly short cleaved inactive products in LV-transduced cells. To improve F8 functionality, we designed two novel F8-BDD genes, one with an insertion of eight specific N-glycosylation sites (F8-N8) and another which restored all N-glycosylation sites (F8-299) in the B domain. Although the overall protein expression was reduced, high coagulation activity (>100-fold) was detected in the supernatants of LV-F8-N8- and LV-F8-299-transduced cells. Protein analysis of F8 and the procoagulation cofactor, von Willebrand Factor, showed enhanced interaction after restoration of B domain glycosylation using F8-299. HA mouse hematopoietic stem cell transplantation studies illustrated that the bleeding phenotype was corrected after LV-F8-N8 or -299 gene transfer into the hematopoietic stem cells. Importantly, the F8-299 modification markedly reduced immunogenicity of the F8 protein in these HA mice. In conclusion, the modified F8-299 gene could be efficiently packaged into LV and, although with reduced expression, produced highly stable and functional F8 protein that corrected the bleeding phenotype without inhibitory immunogenicity. We anticipate that these results will be beneficial in the development of gene therapies against HA.

Medication therapy of high-dose methotrexate: An evidence-based practice guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society.

AIMS: A lot of medication risks related to high-dose methotrexate (HDMTX) therapy still remain to be identified and standardized. This study aims to establish an evidence-based practice guideline for individualized medication of HDMTX. METHODS: The practice guideline was launched by the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society. The guideline was developed following the WHO handbook for guideline development and the methodology of evidence-based medicine (EBM). The guideline was initially registered in the International Practice Guidelines Registry Platform (IPGRP-2017CN021). Systematic reviews were conducted to synthesize available evidence. A multicentre cross-sectional study was conducted using questionnaires to evaluate patients' perception and willingness concerning individualized medication of HDMTX. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to rate the quality of evidence and to grade the strength of recommendations. RESULTS: Multidisciplinary working groups were included in this guideline, including clinicians, pharmacists, methodologists, pharmacologists and pharmacoeconomic specialists. A total of 124 patients were involved to integrate patient values and preferences. Finally, the guideline presents 28 recommendations, regarding evaluation prior to administration (renal function, liver function, pleural effusion, comedications, genetic testing), pre-treatment and routine dosing regimen, therapeutic drug monitoring (necessity, method, timing, target concentration), leucovorin rescue (initial timing, dosage regimen and optimization), and management of toxicities. Of these, 12 are strong recommendations. CONCLUSIONS: We developed an evidence-based practice guideline with respect to HDMTX medication using a rigorous and multidisciplinary approach. This guideline provides comprehensive and practical recommendations involving the whole process of HDMTX administration to health care providers.

BACH2-mediated FOS confers cytarabine resistance via stromal microenvironment alterations in pediatric ALL.

Acute lymphoblastic leukemia (ALL) is an aggressive hematological cancer that mainly affects children. Relapse and chemoresistance result in treatment failure, underlining the need for improved therapies. BTB and CNC homology 2 (BACH2) is a lymphoid-specific transcription repressor recognized as a tumor suppressor in lymphomas, but little is known about its function and regulatory network in pediatric ALL (p-ALL). Herein, we found aberrant BACH2 expression at new diagnosis not only facilitated risk stratification of p-ALL but also served as a sensitive predictor of early treatment response and clinical outcome. Silencing BACH2 in ALL cells increased cell proliferation and accelerated cell cycle progression. BACH2 blockade also promoted cell adhesion to bone marrow stromal cells and conferred cytarabine (Ara-C)-resistant properties to leukemia cells by altering stromal microenvironment. Strikingly, we identified FOS, a transcriptional activator competing with BACH2, as a novel downstream target repressed by BACH2. Blocking FOS by chemical compounds enhanced the effect of Ara-C treatment in both primary p-ALL cells and pre-B-ALL-driven leukemia xenografts and prolonged the survival of tumor-bearing mice. These data highlight an interconnected network of BACH2-FOS, disruption of which could render current chemotherapies more effective and offer a promising therapeutic strategy to overcome Ara-C resistance in p-ALL.

Whole-transcriptome sequencing identifies a distinct subtype of acute lymphoblastic leukemia with predominant genomic abnormalities of EP300 and CREBBP.

Chromosomal translocations are a genomic hallmark of many hematologic malignancies. Often as initiating events, these structural abnormalities result in fusion proteins involving transcription factors important for hematopoietic differentiation and/or signaling molecules regulating cell proliferation and cell cycle. In contrast, epigenetic regulator genes are more frequently targeted by somatic sequence mutations, possibly as secondary events to further potentiate leukemogenesis. Through comprehensive whole-transcriptome sequencing of 231 children with acute lymphoblastic leukemia (ALL), we identified 58 putative functional and predominant fusion genes in 54.1% of patients (n = 125), 31 of which have not been reported previously. In particular, we described a distinct ALL subtype with a characteristic gene expression signature predominantly driven by chromosomal rearrangements of the ZNF384 gene with histone acetyltransferases EP300 and CREBBP ZNF384-rearranged ALL showed significant up-regulation of CLCF1 and BTLA expression, and ZNF384 fusion proteins consistently showed higher activity to promote transcription of these target genes relative to wild-type ZNF384 in vitro. Ectopic expression of EP300-ZNF384 and CREBBP-ZNF384 fusion altered differentiation of mouse hematopoietic stem and progenitor cells and also potentiated oncogenic transformation in vitro. EP300- and CREBBP-ZNF384 fusions resulted in loss of histone lysine acetyltransferase activity in a dominant-negative fashion, with concomitant global reduction of histone acetylation and increased sensitivity of leukemia cells to histone deacetylase inhibitors. In conclusion, our results indicate that gene fusion is a common class of genomic abnormalities in childhood ALL and that recurrent translocations involving EP300 and CREBBP may cause epigenetic deregulation with potential for therapeutic targeting.

ß-catenin promotes MTX resistance of leukemia cells by down-regulating FPGS expression via NF-κB.

BACKGROUND: Aberrant activation of ß-catenin has been shown to play important roles in the chemoresistance of acute lymphoblastic leukemia (ALL), but the involvement and mechanism of ß-catenin in methotrexate (MTX) resistance is poorly understood. In the present study, we demonstrate a critical role of ß-catenin-NF-κB-FPGS pathway in MTX resistance in the human T-lineage ALL cell lines. METHODS: Lentivirus sh-ß-catenin was used to silence the expression of ß-catenin. Flow cytometry was performed to detect apoptosis after MTX treatment. Western blot, real-time PCR, Co-immunoprecipitation (Co-IP), Chromatin immunoprecipitation (ChIP), Re-ChIP, and Luciferase assay were utilized to investigate the relationship among ß-catenin, nuclear factor (NF)-κB, and folypoly-γ-glutamate synthetase (FPGS). RESULTS: Depletion of ß-catenin significantly increased the cytotoxicity of MTX. At the molecular level, knockdown of ß-catenin caused the increase of the protein level of FPGS and NF-κB p65. Furthermore, ß-catenin complexed with NF-κB p65 and directly bound to the FPGS promoter to regulate its expression. In addition, ß-catenin repression prolonged the protein turnover of FPGS. CONCLUSIONS: Taken together, our results demonstrate that ß-catenin may contribute to MTX resistance in leukemia cells via the ß-catenin-NF-κB-FPGS pathway, posing ß-catenin as a potential target for combination treatments during ALL therapy.

Frequency distribution of five SNPs in human GGH gene and their effects on clinical outcomes of Chinese pediatric patients with acute lymphoblastic leukemia.

Methotrexate (MTX) is widely used in the treatment of childhood acute lymphoblastic leukemia (ALL). Gamma-glutamyl hydrolase (GGH) plays an important role in the disposition of MTX. The aim of this study was to investigate the frequency distribution of five SNPs in the human GGH gene and their effects on serum MTX concentrations and clinical outcomes in Chinese children with ALL. Genotyping of 149 pediatric patients for GGH rs11545078 C>T, rs11545077 G>A, rs1800909 T>C, rs11545076 T>G, and rs3758149 C>T was performed using the Sequenom MassARRAY system. Serum MTX concentrations were determined using a fluorescence polarization immunoassay. The five SNPs studied were in strong linkage. The minor allele frequencies for rs11545078, rs11545077, rs1800909, rs11545076, and rs3758149 were 5.3, 15.0, 14.3, 15.0, and 15.0%, respectively. Four haplotypes (CGTTC, CACGT, TACGT, and TATGT) were observed at frequencies of 84.9, 9.8, 4.5, and 0.8%, respectively. The median C/D ratios of serum MTX at 24 h and 42 h in children with variant haplotypes (12.30 and 0.08 µmol/L per g/m², respectively) were higher than those in wild haplotype carriers (11.85 and 0.07 µmol/L per g/m², respectively). The event-free survival of patients with variant haplotypes (89.2%) was significantly better than that of patients with wild haplotypes (71.9%, P < 0.05). The relapse rate in children with variant haplotypes (8.1%) was lower than that in children with wild haplotypes (15.6%). These findings have implications for the efficacious use of MTX in childhood ALL patients.

An improved advanced fragment analysis-based classification and risk stratification of pediatric acute lymphoblastic leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL) contains cytogenetically distinct subtypes that respond differently to cytotoxic drugs. Therefore, subtype classification is important and indispensable in ALL diagnosis. In our previous study, we identified some marker genes in childhood ALL by means of microarray technology and, furthermore, detected the relative expression levels of 57 marker genes and built a comparatively convenient and cost-effective classifier with a prediction accuracy as high as 94% based on the advanced fragment analysis (AFA) technique. METHODS: A more convenient improved AFA (iAFA) technique with one-step multiplex RT-PCR and an anti-contamination system was developed to detect 57 marker genes for ALL. RESULTS: The iAFA assay is much easier and more convenient to perform than the previous AFA assay and has a prediction accuracy of 95.29% in ALL subtypes. The anti-contamination system could effectively prevent the occurrence of lab DNA contamination. We also showed that marker gene expression profiles in pediatric ALL revealed 2 subgroups with different outcomes. Most ALL patients (95.8%) had a good-risk genetic profile, and only 4.2% of ALL patients had a poor-risk genetic profile, which predicted an event-free survival (EFS) of 93.6 ± 1.3% vs 18.8 ± 9.8% at 5 years, respectively (P < 0.001). CONCLUSIONS: Compared to the previous AFA assay, the iAFA technique is more functional, time-saving and labor-saving. It could be a valuable clinical tool for the classification and risk stratification of pediatric ALL patients.

Clinical-biological characteristics and treatment outcomes of pediatric pro-B ALL patients enrolled in BCH-2003 and CCLG-2008 protocol: a study of 121 Chinese children.

BACKGROUND: Although leukemic blast cells of Pro-B cell acute lymphoblastic leukemia (ALL) are arrested at the same stage of B cell differentiation, the immature B cell subtype is still biologically heterogeneous and is associated with diverse outcomes. This study aimed to explore the clinical-biological characteristics of pediatric pro-B ALL and factors associated with outcomes. METHODS: This study enrolled 121 pediatric patients aged 6 months to 14 years with newly diagnosed CD19+CD10- pro-B cell acute lymphoblastic leukemia (pro-B ALL) treated at Beijing Children's Hospital from March 2003 to October 2018. Genetic abnormalities, immunophenotypic markers, minimal residual disease (MRD) at early treatment stage and long-term outcomes of children treated on two consecutive protocols were analyzed. RESULTS: KMT2A rearrangements were the most frequent abnormalities (incidence rate 33.06%), and were associated with lower frequency of CD13, CD33, CD22 and CD34 expression and higher frequency of CD7 and NG2 expression. Higher frequency of CD15 and CD133 expression was found in KMT2A-AFF1 + patients, exclusively. Presence of CD15 and absence of CD34 at diagnosis correlated with the high burden of MRD at the early stage of treatment. Outcomes were more favorable in patients older than 1 year, with absence of CD20 expression and KMT2A rearrangements, and with MRD lower than 1% at the end of induction and 0.1% before consolidation. Increased intensity of chemotherapy based on MRD analysis did not improve outcomes significantly (5-year EFS 73.9 ± 6.5% for BCH-2003 and 76.1 ± 5.3% for CCLG-2008, P = 0.975). Independent adverse prognostic factors were MRD ≥ 0.1% before consolidation and presence of KMT2A gene rearrangements (odds ratios [ORs] 9.424 [95% confidence interval (CI) 3.210, 27.662; P < 0.001]; 4.142 [1.535, 11.715, P = 0.005]; respectively). CONCLUSIONS: Pediatric pro-B ALL is a heterogeneous disease. Genetic analysis and MRD evaluation can predict patients with dismal prognosis; however, intensive chemotherapy alone does not improve outcomes of these patients and targeted therapy or hematopoietic stem cell transplantation may be required.

Long-term follow-up of children with acute promyelocytic leukemia treated with Beijing Children's Hospital APL 2005 protocol (BCH-APL 2005).

We studied the outcomes of children with APL treated by the Beijing Children's Hospital's (BCH) acute promyelocytic leukemia (APL) 2005 protocol (BCH-APL2005). The clinical data of 77 patients enrolled from January 2005 to June 2015 were analyzed retrospectively. The hematologic complete remission (CR) rate and overall survival (OS) rate were evaluated between standard-risk (SR) and high-risk (HR) groups. Prognostic factors and complications were investigated in these two groups. CR in the SR and HR groups was 96.4% (54/56) and 85.7% (18/21), respectively, while the 10-year OS was 94.6% (53/56) and 76.2% (16/21), respectively. The cumulative incidence of early death was 6.5% (5/77), and the SR and HR groups were 1.8% (1/56) and 19.0% (4/21), respectively. Only two patients relapsed, and the relapse rate was 2.6% (2/77). According to Kaplan-Meier analysis, the SR group had a significantly better long-term survival than HR counterparts (p= .016). Initial leukocyte count was the only prognostic factor (p= .016) by univariate analysis, while other factors, such as FLT3-ITD and platelet count, had no correlation with prognosis. In addition, early deaths were mainly due to intracranial hemorrhage. Although the combination of all-trans retinoic acid (ATRA) and chemotherapy can improve the outcome of APL patients, the early deaths and anthracycline-related cardiac toxicity were relatively higher in our study. Current efforts focus on reducing or even avoiding chemotherapy in APL children and rest on the frontline regimen of intravenous arsenic trioxide or oral realgar-indigo naturalis formula plus ATRA, which is the direction for APL treatment.

Phosphorylation of serine/arginine-rich splicing factor 1 at tyrosine 19 promotes cell proliferation in pediatric acute lymphoblastic leukemia.

Serine/arginine-rich splicing factor 1 (SRSF1) has been linked to various human cancers including pediatric acute lymphoblastic leukemia (ALL). Our previous study has shown that SRSF1 potentially contributes to leukemogenesis; however, its underlying mechanism remains unclear. In this study, leukemic cells were isolated from pediatric ALL bone marrow samples, followed by immunoprecipitation assays and mass spectrometry analysis specific to SRSF1. Subcellular localization of the SRSF1 protein and its mutants were analyzed by immunofluorescence staining. Cell growth, colony formation, cell apoptosis, and the cell cycle were investigated using stable leukemic cell lines generated with lentivirus-mediated overexpressed WT or mutant plasmids. Cytotoxicity of the Tie2 kinase inhibitor was also evaluated. Our results showed the phosphorylation of SRSF1 at tyrosine 19 (Tyr-19) was identified in newly diagnosed ALL samples, but not in complete remission or normal control samples. Compared to the SRSF1 WT cells, the missense mutants of the Tyr-19 phosphorylation affected the subcellular localization of SRSF1. In addition, the Tyr-19 phosphorylation of SRSF1 also led to increased cell proliferation and enhanced colony-forming properties by promoting the cell cycle. Remarkably, we further identified the kinase Tie2 as a potential therapeutic target in leukemia cells. In conclusion, we identify for the first time that the phosphorylation state of SRSF1 is linked to different phases in pediatric ALL. The Tyr-19 phosphorylation of SRSF1 disrupts its subcellular localization and promotes proliferation in leukemia cells by driving cell-cycle progression. Inhibitors targeting Tie2 kinase that could catalyze Tyr-19 phosphorylation of SRSF1 offer a promising therapeutic target for treatment of pediatric ALL.

The prognostic potential of coilin in association with p27 expression in pediatric acute lymphoblastic leukemia for disease relapse.

BACKGROUND: Cajal body (CB) is a nucleic organelle where small nuclear ribonucleoproteins undergo modification, maturation, splicing and/or assembly. Coilin is the marker structural protein of CBs. The expression level and cellular localization of coilin is sensitive to chemotherapeutic reagents, such as cisplatin. The gene of cyclin-dependent kinase inhibitor 1B (p27) is located with a high incidence translocation region of leukemic chromosomes, and its expression was of prognosis values in a variety of adult leukemia types. The exact profile and associated functions of coilin, as well as p27, in children's acute lymphoblastic leukemia (ALL) is obscure. METHODS: Bone marrow samples from 144 patients with ALL were collected. The expression levels of coilin and p27 were detected by qRT-PCR. The patient cohort was divided into low and high groups of coilin and p27 respectively. The prognosis and clinicobiological characteristics of different groups were investigated, especially focused on the treatment outcome. Leukemia cells of Reh or RS4;11 were exposed to different concentrations of DNR, prior to the detection for morphological changes of coilin by immunofluorescence. In Reh cells, lentivirus sh-coilin was used to silence coilin expression. Western blotting was used to detect coilin and p27 expression; flow cytometry was used for cell cycle and apoptosis assay; MTS method was used for measuring cell viability to examine the drug sensitivity of DNR. RESULTS: In this study, we found that daunorubicin was able to induce significant morphological changes of CBs in Reh and RS4;11 cells. Knockdown the expression of coilin increased the sensitivity to daunorubicin and inhibited the expression of p27 in Reh cells, and led to increased apoptosis. Importantly, not only the levels of coilin and p27 mRNA expression at initial diagnosis ALL children are markedly higher than those at complete remission (CR), but also both coilin and p27 expression in the relapsed patients was observed significantly higher comparing to the continuous CR patients. The 4-year EFS and RFS indicated that low levels of both coilin and p27 group favored better prognosis (p < 0.05). CONCLUSIONS: Our results indicated that consideration of coilin and p27 levels could be a prognostic reference for predicting the outcome of pediatric ALL patients, especially for disease recurrence. Reduction of coilin expression was sufficient to increase the sensitivity of leukemic cells to daunorubicin treatments, and during which possibly involved functions of p27 in cell cycle regulation and its effects on cell apoptosis.

Outcome of children with newly diagnosed acute lymphoblastic leukemia treated with CCLG-ALL 2008: The first nation-wide prospective multicenter study in China.

Acute lymphoblastic leukemia (ALL) is the most common malignancy among children. The trial Chinese Children Leukemia Group (CCLG)-ALL 2008 was a prospective clinical trial designed to improve treatment outcome of childhood ALL through the first nation-wide collaborative study in China. Totally 2231 patients were recruited from ten tertiary hospitals in eight cities. The patients were stratified according to clinical-biological characteristics and early treatment response. Standard risk (SR) and intermediate risk (IR) groups were treated with a modified BFM based protocol, and there was 25%-50% dose reduction during intensification phases in the SR group. Patients in high risk (HR) group received a more intensive maintenance treatment. Minimal residual disease (MRD) monitoring with treatment adjustment was performed in two hospitals (the MRD group). Complete remission (CR) was achieved in 2100 patients (94.1%). At five years, the estimate for overall survival (OS) and event-free survival (EFS) of the whole group was 85.3% and 79.9%, respectively. The cumulative incidence of relapse (CIR) was 15.3% at five years. The OS, EFS and CIR for the SR group were 91.5%, 87.9%, and 9.7%, respectively. The outcome of the MRD group is better than the non-MRD group (5y-EFS: 82.4% vs 78.3%, P = .038; 5y-CIR: 10.7% vs 18.0%, P < .001). Our results demonstrated that the large-scale multicenter trial for pediatric ALL was feasible in China. Dose reduction in the SR group could achieve high EFS. MRD-based risk stratification might improve the treatment outcome for childhood ALL.