[Clinical Analysis of Philadelphia Chromosome-Like Acute Lymphoblastic Leukemia in Children].

OBJECTIVE: To explore the clinical characteristics, molecular characteristics, treatment and prognosis of pediatric Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) with a therapeutic target. METHODS: A total of 27 patients of Ph-like ALL with targeted drug target were initially diagnosed in Children's Hospital of Soochow University from December 2017 to June 2021. The data of age, gender, white blood cell (WBC) count at initial diagnosis, genetic characteristics, molecular biological changes, chemotherapy regimen, different targeted drugs were given, and minimal residual disease (MRD) on day 19, MRD on day 46, whether hematopoietic stem cell transplantation (HSCT) were retrospective analyed, and the clinical characteristics and treatment effect were summarized. Survival analysis was performed by Kaplan-Meier method. RESULTS: The intensity of chemotherapy was adjusted according to the MRD level during induced remission therapy in 27 patients, 10 patients were treated with targeted drugs during treatment, and 3 patients were bridged with HSCT, 1 patient died and 2 patients survived. Among the 24 patients who did not receive HSCT, 1 patient developed relapse, and achieved complete remission (CR) after treatment with chimeric antigen receptors T cells (CAR-T). The 3-year overall survival, 3-year relapse-free survival and 3-year event-free survival rate of 27 patients were (95.5±4.4)%, (95.0±4.9)% and (90.7±6.3)% respectively. CONCLUSION: Risk stratification chemotherapy based on MRD monitoring can improve the prognosis of Ph-like ALL in children, combined with targeted drugs can achieve complete remission as soon as possible in children whose chemotherapy response is poor, and sequential CAR-T and HSCT can significantly improve the therapeutic effect of Ph-like ALL in children whose MRD is continuously positive during induced remission therapy.

[Effect of Plasmacytoid Dendritic Cell Dose in Grafts on CMV Infection after Allogeneic Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To investigate the correlation between plasmacytoid dendritic cell (pDC) dose in grafts and the occurrence of cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The clinical data of 80 children who received allo-HSCT in Children's Hospital of Soochow University from August 20, 2020 to June 11, 2021 were retrospectively analyzed. Proportions of DC subsets and T-cell subsets in grafts were detected by flow cytometry in order to calculate infused cell dose of each cell. Weekly monitoring of CMV-DNA copies in peripheral blood for each child were performed after transplantation. The last follow-up date was December 31, 2021. RESULTS: All the children gained hematopoietic reconstitution. CMV infection was observed in 51 children (63.8%±5.4%) within the first 100 days after transplantation, including 2 cases developing CMV disease. Univariate analysis indicated that infused doses of DC and pDC were significantly associated with CMV infection within 100 days after allo-HSCT (P <0.05). Multivariate analysis indicated that a high dose infusion of pDC was an independent protective factor for CMV infection within 100 days after allo-HSCT (P <0.05). By the end of follow-up, 7 children died of transplantation-related complications, including 2 deaths from CMV disease, 2 deaths from extensive chronic graft-versus-host disease, and 3 deaths from capillary leak syndrome. The overall survival rate was 91.2%. CONCLUSION: The pDC in grafts may be associated with early infection of CMV after allo-HSCT, while a high infused pDC dose may serve as a protective factor for CMV infection after transplantation.

[Effect of Chemotherapy Course Delay on the Relapse of Paediatric B-cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To investigate the effect of course delay of CCLG-ALL-2008 regimen on the relapse of paediatric B-cell acute lymphoblastic leukemia (B-ALL) patients. METHODS: Paediatric B-ALL patients newly diagnosed and treated with CCLG-ALL-2008 regimen in the Children's Hospital of Soochow University from January 2011 to December 2014 were retrospectively analyzed to clarify the relationship between chemotherapy course delay and relapse, and explore the causes of course delay which led to relapse. Patients were followed up until July 2019. RESULTS: The correlation between treatment delay (number of weeks) and relapse rate was statistically significant (P=0.034), and hazard ratio indicated that longer than 4 weeks had a significant effect. The effect of positive minimal residual disease (MRD) (1×10-4≤MRD≤1×10-2) at the 12th week on the relapse rate was also statistically significant (P=0.041). Among the causes of treatment delay, the effect of myelosuppression on the relapse rate was statistically significant (P=0.01). CONCLUSION: Treatment delay exceeding 4 weeks, positive MRD at the 12th week, and myelosuppression are independent prognostic factors for relapse.

[Efficacy of Chimeric Antigen Receptor T Cell in the Treatment of Refractory/Recurrent B Acute Lymphocytic Leukemia in Children].

OBJECTIVE: To observe the efficacy of chimeric antigen receptor T cell (CAR-T) in the treatment of children with refractory/recurrent B acute lymphocytic leukemia (B-ALL). METHODS: Thirty-two patients with r/r B-ALL were treated by CAR-T, the recurrence and death respectively were the end point events to evaluate the efficacy and safety of CAR-T. RESULTS: The median age of the patients was 7.5 (2-17.5) years old; 40 times CAR-T were received in all patients and the median number of CAR-T was 0.9×107/kg; efficacy evaluation showed that 2 cases died before the first evaluation. Thirty patients showed that 3, 6, and 9-moth RFS was (96.3±3.6)%, (81.4±8.6)% and (65.3±12.5)%, respectively, while 3, 6, and 9-month OS was all 100%, and 12, 24-month OS was (94.7±5.1)% and (76±12.8)%. BM blasts≥36% before reinfusion and ferritin peak≥2 500 ng/ml within two weeks of CAR-T cell reinfusion were associated with recurrence. Adverse reactions mainly included cytokine release syndrome (CRS) and CART-cell-related encephalopathy syndrome (CRES), CRS appeared in 26 patients within a week of CAR-T cell reinfusion. CRES reaction was detected in 12 patients. Eighteen patients received intravenous drip of tocilizumab, among them, 12 combined with glucocorticoid. CRS and CRES reactions were relieved within one week after treatment. Hormone dosage was related to the duration of remission in patients, and the cumulative dose of methylprednisolone≥8 mg/kg showed a poor prognosis. CONCLUSION: CAR-T is a safe and effective treatment for r/r B-ALL, most CRS and CRES reactions are reversible. BM blasts ≥36% before reinfusion and cumulative dose of methylprednisolone ≥8 mg/kg after reinfusion both affect the therapeutic effect. Ferritin≥2 500 ng/ml within two weeks after reinfusion is related to disease recurrence and is an independent prognostic risk factor.

[The Factors Affecting Relapse in Pediatric B-cell Acute Lymphoblastic Leukemia Patients without Prognostic Fusion Genes Following Up for 10 years].

OBJECTIVE: To analyze the efficacy of children with B-cell acute lymphoblastic leukemia (B-ALL) without prognostic fusion genes treated by CCLG-ALL 2008, and investigate the related factors affecting the recurrence of the patients. METHODS: B-ALL patients without prognostic fusion genes treated by the protocol of CCLG-ALL 2008 in our hospital from March 2008 to December 2012 were retrospectively analyzed. Follow-up time was ended in August 31, 2019. The median follow-up time was 92 months (range 0-136 months). Kaplan-Meier was used to detect the RFS, and COX multivariate regression analysis was employed to identify the independent factors affecting the recurrence of the patients. RESULTS: There were 140 males and 99 females enrolled in this study. The ratio of male to female was 1.41∶1. The median age was 4.4 years old and the median number of WBC at initial stage was 4.98×109/L. There were 77 cases relapsed during the observation while 162 without relapsed, 16 cases lost to follow-up and 72 cases died. The recurrence and mortality rate was 32.22% and 30.1%, respectively, in which 45 cases died of recurrence (62.5% of the total deaths). Univariate analysis showed that the age≥6 years old, WBC >100×109/L, the bone marrow blasts on day 15≥25%, the bone marrow minimal residual disease (MRD) at week 12 >10-4, and the higher risk were the main factors affecting the recurrence of the patients (P<0.05). Multivariate COX regression analysis showed that age≥6 years old, WBC >100×109/L, bone marrow MRD >10-4 at the 12th week were the independent risk factors affecting recurrence of the patients. CONCLUSION: Age, initial WBC, and bone marrow MRD at the 12th week were correlated with recurrence in children with B-ALL without prognostic fusion genes, which can be used as prognostic indices of recurrence risk in clinical.

[The Factors Related to Treatment Failure in Children with Acute Lymphoblastic Leukemia].

OBJECTIVE: To analyze the efficacy of CCLG-ALL-2008 protocol and the related factors of treatment failure in children with acute lymphoblastic leukemia (ALL). METHODS: The clinical data of 400 children newly-diagnosed ALL in Children's Hospital of Soochow University from March 1, 2008 to December 31, 2012 was retrospectively analyzed. All the children accepted CCLG-ALL-2008 protocol, and were followed-up until October 2019. The dates of relapse, death and causes of death were recorded. Treatment failure was defined as relapse, non-relapse death, and secondary tumor. RESULTS: Following-up for 10 years, there were 152 cases relapse or non-relapse death, the treatment failure rate was 38%, including 122 relapse (80.3%), 30 non-relapse deaths (19.7%) which included 7 cases (4 cases died of infection and 3 cases died of bleeding) died of treatment (23.3% of non-relapse deaths), 8 cases died of minimal residual disease (MRD) continuous positive (26.7% of non-relapse deaths) and 15 cases died of financial burden (50% of non-relapse deaths). According to the relapse stage, 37 cases (30%) in very early stage, 38 cases (31%) in early stage, and 47 cases (39%) in late stage, while according to the relapse site, 107 cases relapsed in bone marrow, 3 cases in testis, 3 cases in central nervous system (CNS), 5 cases in bone marrow plus testis and 4 cases in bone marrow plus CNS. Bone marrow relapse was the main cause of death in 89 cases, followed by nervous system. Initially diagnosed WBC count (≥50×109/L), T-cell immunophenotype, and MRD-positive at week 12 were the independent risk prognostic factors for relapse in children with ALL, while age (≥10 years), initially diagnosed WBC count (≥50×109/L), M3 bone marrow on day 15, and MRD-positive at week 12 were the independent risk factors due to treatment failure. No secondary tumors were found during the follow-up for 10 years. CONCLUSION: Relapse is the main cause of treatment failure in children with ALL. The initially diagnosed WBC count, immunophenotype and MRD at week 12 were the independent prognostic factors for relapse of the patients. Financial burden accounts for a large proportion of non-relapse death.

[Expression and Clinical Significance of Long Non-coding RNA AC002454.1 in Children with Acute Leukemia].

OBJECTIVE: To study the difference of long non coding RNA (lncRNA) expression profile in bone marrow specimens of children with acute leukemia (AL) and other hematological disease children with normal bone marrows as controls, to screen the lncRNA related with childhood hematological diseases, and to explore the expression of lncRNA AC002454.1 and its clinical significance in AL children. METHODS: The microarray gene chip technology was used to statistically analyze the lncRNA in bone marrow cells of newly diagnose AL children and control children. Ninty-seren differentially expressed lncRNAs were selected. The bone marrow specimens of ALL children (21 cases), AML children (22 cases) and control children (21 cases) were verified and compared by using qRT-PCR; then the lncRNA with maximum differential expression-lncRNA AC002454.1 was selected and used to analyze the relation of relative expression level with clinical indicators. RESULTS: The microarray gene chip detection showed that 1 884 differentially expressed lncRNA were found in ALL children, and 4 289 differentically expressed lncRNA were found in AML children. The results confirming these differentically expressed lncRNA by qRT-PCR showed that 9 lncRNA expression were significantly up-regulated in ALL children, and 12 lncRNA expression were significantly up-regulated in AML children. Among these up-regulated lncRNA, the difference of AC002454.1 expression was most significant in ALL and AML children (P＜0.05, P＜0.01). The detection showed that there was a significant difference, in AC002454.1 relative expression level of newly diagnosed T-ALL and B-ALL children (P＜0.01), moreover, this difference also was found in ALL and AML children (P＜0.05). The detection analysis showed that there was no statistical difference in AC002454.1 relative expression level among the different sex, age, WBC count at initial diagnosis, chromosome, fusion gene, and risk stratification (P＞0.05 for all). CONCLUSION: The lncRNA expression profile of AL children has been gained by using the lncRNA microarray gene chip technicology. AC002454.1 the significantly high expression exist in AL children, which relates with immunotyping and prognosis of AL children in a certain degree.

Proteomic analysis for identifying the differences in molecular profiling between fanconi anaemia and aplastic anaemia.

Treatment and prognosis of Fanconi anaemia (FA) and acquired aplastic anaemia (AA) differ. However, delayed and inappropriate treatments are administered in FA due to its similarities to AA in presentation. The objective of the current study was to elucidate differences between the molecular mechanisms underlying FA and AA as well as to identify biomarkers and pathways associated with FA via bioinformatics analyses. Proteomic data were obtained from bone marrow samples of patients with FA and AA. Gene ontology analysis was performed using a Database for Annotation, Visualization and Integrated Discovery. KEGG pathway enrichment analyses were conducted using the ClueGO plug-in in Cytoscape. A DEP-associated protein-protein interaction (PPI) network was constructed using STRING and visualized in Cytoscape. A total of 114 DEPs, including 71 upregulated proteins and 43 downregulated proteins, were present in the FA samples, compared with those in the AA samples. Upregulated proteins were enriched in the nucleosome assembly, canonical glycolysis, glycolytic process, and the glycolysis/gluconeogenesis pathway, whereas downregulated proteins were enriched in relation to immune response, negative regulation of apoptosis, proteolysis and CoA biosynthesis. Eight hub proteins with a high degree of connectivity were obtained as follows: alpha-enolase (ENO1), HSP90AA1, phosphoglycerate kinase 1 (PGK1), HSP90AB1, ACTC1, ACTBL2, EEF1A1 and CFL1. Upregulation of ENO1 and CFL1 in patients with FA was confirmed through a WB experiment, and substantiated by the results of data analyses. Bioinformatics analyses are useful for identification of biomarkers and pathways associated with FA and AA. Some crucial DEPs, such as ENO1, PGK1, ACTC1, ACTBL2, EEF1A1 and CFL1, may play an important role in FA and show potential as serological markers for its early diagnosis.

[Analysis of Correlation of WAS Gene Mutations with Clinical Phenotype].

OBJECTIVE: To investigate the gene mutation of patients with WAS gene defect and its correlation with clinical manifestations. METHODS: Thirty-one patients consulted in Children's Hospital of Soochow University from January 2013 to February 2018 were enrolled in this study. The hot pot mutations of WAS gene in 31 patients were detected and related clinical phenotypes were analyzed retrospectively. RESULTS: All patients were male. The median onset age was 1 month (range, 0-83 months). Nine mutants were reported as novel mutations among 25 mutants detected in 31 patients, including c.1234_1235dupCC, c.1093-1097delG, c.28-30dupC, c.436G>T, c.273 + 10_273 + 11dupCC, c.995_996insG, c.1010T>A, c.332_333delCC and c.683C>T mutations. There were 25 cases of classic WAS which mutations included missense mutation, deletion mutation, insertion mutation, splicing mutation and nonsense mutation, 2 cases of X-linked thrombocytopenia (XLT) were induced by missense mutation, 1 case of intermittent X-linked thrombocytopenia (IXLT) was induced by splicing mutation, 2 cases of X-linked pancytopenia were induced by missense mutation. Intravenous immunoglobulin (IVIG) and glucocorticoid therapy in IXLT patient was effective, and remission could be sustained, platelets could be increased in the short-term in treated XLT patients, but only a small part of classic WAS patients(8.0%) showed transient response to it, the IVIG and glucocorticoid therapy did not improve the status of platelet in XLP patients. Immune laboratory examination showed that CD3+ was decreased in 60.0% patients, CD19+ was decreased in 12.0% patients, and CD56+CD16+ in 4 patients was decreased, accounting for 16.0%. Out of 24 patients, 22 patients were alive after treated with hematopoietic stem cell transplantation (HSCT), 4 patients who were not given HSCT died of brain bleeding and severe infection, 1 patient diagnosed as IXLT got remission and survived. CONCLUSION: WAS gene defect is an important basis for the diagnosis of WAS and related diseases. IVIG plus glucocorticoid therapy is less effective for fewer patients, the HSCT is an effective treatment for WAS.

[Safety and Efficacy of VDMP Re-induction Regimen in Chinese Children with Relapsed Acute Lymphoblastic Leukemia-A Report from Jiangsu Childhood Hematology Group].

OBJECTIVE: To evaluate the therapeutic safety and efficacy of VDMP re-induction regimen in Chinese children with relapsed acute lymphoblastic leukemia (ALL). METHODS: Forty-one patients with relapsed ALL were prospectively enrolled in this study. All the patients were distributed in 3 children's hospitals and treated with VDMP regimen as the first re-induction chemotherapy. Therapeutic efficacy and side-effects were analyzed. RESULTS: The ratio of male to female was 27:14. The median age was 7.9 (2.2-15.4) years old. Patients relapsed at very early, early, and late stage were 7 cases, 11 cases, and 23 cases, respectively.The immunophenotype analysis showed that 38 cases were B-ALL, and 3 cases were T-ALL. All patients suffered from grade 4 of neutropenia and forty(97.6%) cases got infection, of them one case died. Thirty-nine(95.1%) cases had nonhematologic adverse event at least one organ involved grade 3 in 38 out of 41 cases, the VDMP therapy was completed, 34(89.5%) cases achieved a complete remission (CR), 1 case achieved partial remission(PR), and 3 cases didn't get remission. Follow-up data of 38 cases with completing VDMP chemotherapy were obtained, only one case was lost. Among 37 cases available for evaluation, 16 cases received allo-hematopoietic stem cell transplantation(allo-HSCT) after chemotherapy, and 13 patients survived, while 21 cases did not receive allo-HSCT(treated with chemotherapy only), and 8 patients survived.The overall survival rate of allo-HSCT group was significantly higher than that of those treated with chemotherapy only(P<0.05). CONCLUSION: VDMP re-induction regimen is effective and well tolerable for pafients in the treated children with relapsed ALL. After remission, allo-HSCT is recommended with the aim of long survival.

Clinical presentation and outcome of pediatric patients with hemophagocytic lymphohistiocytosis in China: A retrospective multicenter study.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a heterogeneous disease with major diagnostic and therapeutic difficulties. A large-scale multicenter study of pediatric HLH is still lacking in China. PROCEDURE: The Histiocytosis Study Group of the Chinese Pediatric Society conducted this retrospective study in 2014. A total of 323 patients diagnosed with HLH between 2011 and 2013 from 12 hospitals were registered. RESULTS: The median age at diagnosis was 2.2 years (range, 0-14.6 years), with a peak age of HLH onset at 0 to 3 years (63%). Mutations in HLH-related genes were found in 27.9% (24/86) patients who underwent genetic testing. PRF1, UNC13D, STXBP2 and LYST were the predominant genes involved. Sixteen patients (66.7%) presented with only monoallelic mutations in one gene. Epstein-Barr virus (EBV) infection was the major condition related to HLH, which was documented in 74.4% (201/270) of the patients who underwent EBV detection. Of 252 evaluable patients, 64.7% (163) achieved non-active disease at the eighth week and patients treated with a protocol containing etoposide presented higher remission rates (75.6% vs. 46.8%, P < 0.001). In multivariate analysis, a younger age at diagnosis (<12 months), platelet count less than 80×109 /L, central nervous system involvement, and initial treatment using a protocol without etoposide (not HLH-94/04) were independent prognostic factors indicating resistant disease. DISCUSSION: This study first multicenter assessment of HLH in China shows some different features in Chinese children with HLH compared with those in western countries, including older age, vulnerability to EBV infection, and a high proportion of patients with single monoallelic genetic mutations.

mRNA expression profiling of histone modifying enzymes in pediatric acute monoblastic leukemia.

Histone modification is dysregulated in various types of cancers, including hematological malignancies. However, the expression profile of histone-modifying enzymes in pediatric acute monoblastic leukemia (AML FAB M5) has not been investigated. In this study, we evaluated the mRNA expression profile of 85 genes that encode enzymes involved in histone-modification in 27 pediatric AML FAB M5 samples by using a novel real-time PCR array. We obtained a gene cluster consisting of a total of 28 genes (15 up-regulated genes and 13 down-regulated genes). This gene signature revealed up-regulated expression of putative oncogenes GCN5L2, SETD8, KDM5C, AURKA and AURKB, and downregulated putative tumor suppressor genes (TSGs) EP300, PRMT3, PRMT8 and NOTCH2. We investigated possible biological interactions between differentially expressed genes using ingenuity pathway analysis (IPA) and found 12 significant networks. Among these, gene expression, cancer, and embryonic development showed the highest number of networks with 39 focus molecules and had an associated significance score of 68. Further, Rb, CDKN2C, and E2F1 were found to be upstream regulators of histone-modifying enzymes. This study provides additional insights into the molecular pathogenesis of pediatric AML FAB M5. These genes represent interesting targets with potential for diagnostic, prognostic and therapeutic application in pediatric AML patients.

Microarray profiling of bone marrow long non-coding RNA expression in Chinese pediatric acute myeloid leukemia patients.

Long non-coding RNA (lncRNA) plays a role in gene transcription, protein expression and epigenetic regulation; and altered expression results in cancer development. Acute myeloid leukemia (AML) is rare in children; and thus, this study profiled lncRNA expression in bone marrow samples from pediatric AML patients. Arraystar Human LncRNA Array V3.0 was used to profile differentially expressed lncRNAs in three bone marrow samples obtained from each pediatric AML patient and normal controls. Quantitative polymerase chain reaction (qRT-PCR) was performed to confirm dysregulated lncRNA expressions in 22 AML bone marrow samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to construct the lncRNA-mRNA co-expression network. A total of 372 dysregulated lncRNAs (difference ≥10-fold) were found in pediatric AML patients compared to normal controls. Fifty-one mRNA levels were significantly upregulated, while 85 mRNA levels were significantly downregulated by >10-fold in pediatric AML, compared to normal controls. GO terms and KEGG pathway annotation data revealed that cell cycle pathway-related genes were significantly associated with pediatric AML. As confirmed by qRT-PCR, expression of 24 of 97 lncRNA was altered in pediatric AML compared to normal controls. In pediatric AML, ENST00000435695 was the most upregulated lncRNA, while ENST00000415964 was the most downregulated lncRNA. Data from this study revealed dysregulated lncRNAs and mRNAs in pediatric AML versus normal controls that could form gene pathways to regulate cell cycle progression and immunoresponse. Further studies are required to determine whether these lncRNAs could serve as novel therapeutic targets and bbdiagnostic biomarkers in pediatric AML.

Hypermethylation of the GATA binding protein 4 (GATA4) promoter in Chinese pediatric acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is the second-most common form of leukemia in children. Aberrant DNA methylation patterns are a characteristic feature of AML. GATA4 has been suggested to be a tumor suppressor gene regulated by promoter hypermethylation in various types of human cancers although the expression and promoter methylation of GATA4 in pediatric AML is still unclear. METHODS: Transcriptional expression levels of GATA4 were evaluated by semi-quantitative and real-time PCR. Methylation status was investigated by methylation-specific PCR (MSP) and bisulfate genomic sequencing (BGS). The prognostic significance of GATA4 expression and promoter methylation was assessed in 105 cases of Chinese pediatric acute myeloid leukemia patients with clinical follow-up records. RESULTS: MSP and BGS analysis showed that the GATA4 gene promoter is hypermethylated in AML cells, such as the HL-60 and MV4-11 human myeloid leukemia cell lines. 5-Aza treatment significantly upregulated GATA4 expression in HL-60 and MV4-11 cells. Aberrant methylation of GATA4 was observed in 15.0 % (3/20) of the normal bone marrow control samples compared to 56.2 % (59/105) of the pediatric AML samples. GATA4 transcript levels were significantly decreased in AML patients (33.06 ± 70.94; P = 0.011) compared to normal bone marrow/idiopathic thrombocytopenic purpura controls (116.76 ± 105.39). GATA4 promoter methylation was correlated with patient leukocyte counts (WBC, white blood cells) (P = 0.035) and minimal residual disease MRD (P = 0.031). Kaplan-Meier survival analysis revealed significantly shorter overall survival time in patients with GATA4 promoter methylation (P = 0.014). CONCLUSIONS: Epigenetic inactivation of GATA4 by promoter hypermethylation was observed in both AML cell lines and pediatric AML samples; our study implicates GATA4 as a putative tumor suppressor gene in pediatric AML. In addition, our findings imply that GATA4 promoter methylation is correlated with WBC and MRD. Kaplan-Meier survival analysis revealed significantly shorter overall survival in pediatric AML with GATA4 promoter methylation but multivariate analysis shows that it is not an independent factor. However, further research focusing on the mechanism of GATA4 in pediatric leukemia is required.

[Efficacy Analysis of Allogeneic Hematopoietic Stem Cell Transplantation for Children with Severe Aplastic Anemia].

OBJECTIVE: To study the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with severe aplastic anemia (SAA). METHODS: A total of 11 children with SAA were treated with HLA matched siblings (n = 7), umbilical cord blood (n = 2) and haploidentical HSCT (n = 2). RESULTS: Among 11 children patients, 10 patients achieved engraftment, but 3 children patients experienced secondary graft failure, after donor lymphocyte infusions (DLI), they achieved engraftment again. One patient received cord blood transplantation and experienced primary graft rejection, but acquired autologous recovery. The median time for neutrophils to reach over 0.5 × 10(9)/L was 14 days (10-19 days) in the 9 children received bone marrow or bone marrow and peripheral blood allo-HSCT, while the median time for platelets to reach over 20 × 10(9)/L was 17 days (8-42 days). For the patient received double cord blood transplantation, the time of neutrophile and platelet level recovery was 16 days and 41 days, respectively. CONCLUSION: If HLA-matched sibling donor is available, allo-HSCT can be recommended as the first line of treatment for children with SAA. It is feasible for children with SAA to receive allo-HSCT from selective donor, including cord blood and haploidentical HSCT. Donor lymphocyte infusions can improve engraftment.

Analyzing the gene expression profile of anaplastic histology Wilms' tumor with real-time polymerase chain reaction arrays.

BACKGROUND: Wilms' tumor (WT) is one of the most common malignant neoplasms of the urinary tract in children. Anaplastic histology (unfavorable histology) accounts for about 10% of whole WTs, and it is the single most important histologic predictor of treatment response and survival in patients with WT; however, until now the molecular basis of this phenotype is not very clearly. METHODS: A real-time polymerase chain reaction (PCR) array was designed and tested. Next, the gene expression profile of pediatric anaplastic histology WT and normal adjacent tissues were analyzed. These expression data were anlyzed with Multi Experiment View (MEV) cluster software further. Datasets representing genes with altered expression profiles derived from cluster analyses were imported into the Ingenuity Pathway Analysis Tool (IPA). RESULTS: 88 real-time PCR primer pairs for quantitative gene expression analysis of key genes involved in pediatric anaplastic histology WT were designed and tested. The gene expression profile of pediatric anaplastic histology WT is significantly different from adjacent normal controls; we identified 15 genes that are up-regulated and 16 genes that are down-regulated in the former. To investigate biological interactions of these differently regulated genes, datasets representing genes with altered expression profiles were imported into the IPA for further analysis, which revealed three significant networks: Cancer, Hematological Disease, and Gene Expression, which included 27 focus molecules and a significance score of 43. The IPA analysis also grouped the differentially expressed genes into biological mechanisms related to Cell Death and Survival 1.15E(-12), Cellular Development 2.84E(-11), Cellular Growth and Proliferation 2.84E(-11), Gene Expression 4.43E(-10), and DNA Replication, Recombination, and Repair 1.39E(-07). The important upstream regulators of pediatric anaplastic histology WT were TP53 and TGFß1 signaling (P = 1.15E(-14) and 3.79E(-13), respectively). CONCLUSIONS: Our study demonstrates that the gene expression profile of pediatric anaplastic histology WT is significantly different from adjacent normal tissues with real-time PCR array. We identified some genes that are dysregulated in pediatric anaplastic histology WT for the first time, such as HDAC7, and IPA analysis showed the most important pathways for pediatric anaplastic histology WT are TP53 and TGFß1 signaling. This work may provide new clues into the molecular mechanisms behind pediatric anaplastic histology WT.

Early B-cell factor 3 (EBF3) is a novel tumor suppressor gene with promoter hypermethylation in pediatric acute myeloid leukemia.

BACKGROUND: Pediatric acute myeloid leukemia (AML) comprises up to 20% of all childhood leukemia. Recent research shows that aberrant DNA methylation patterning may play a role in leukemogenesis. The epigenetic silencing of the EBF3 locus is very frequent in glioblastoma. However, the expression profiles and molecular function of EBF3 in pediatric AML is still unclear. METHODS: Twelve human acute leukemia cell lines, 105 pediatric AML samples and 30 normal bone marrow/idiopathic thrombocytopenic purpura (NBM/ITP) control samples were analyzed. Transcriptional level of EBF3 was evaluated by semi-quantitative and real-time PCR. EBF3 methylation status was determined by methylation specific PCR (MSP) and bisulfite genomic sequencing (BGS). The molecular mechanism of EBF3 was investigated by apoptosis assays and PCR array analysis. RESULTS: EBF3 promoter was hypermethylated in 10/12 leukemia cell lines. Aberrant EBF3 methylation was observed in 42.9% (45/105) of the pediatric AML samples using MSP analysis, and the BGS results confirmed promoter methylation. EBF3 expression was decreased in the AML samples compared with control. Methylated samples revealed similar survival outcomes by Kaplan-Meier survival analysis. EBF3 overexpression significantly inhibited cell proliferation and increased apoptosis. Real-time PCR array analysis revealed 93 dysregulated genes possibly implicated in the apoptosis of EBF3-induced AML cells. CONCLUSION: In this study, we firstly identified epigenetic inactivation of EBF3 in both AML cell lines and pediatric AML samples for the first time. Our findings also showed for the first time that transcriptional overexpression of EBF3 could inhibit proliferation and induce apoptosis in AML cells. We identified 93 dysregulated apoptosis-related genes in EBF3-overexpressing, including DCC, AIFM2 and DAPK1. Most of these genes have never been related with EBF3 over expression. These results may provide new insights into the molecular mechanism of EBF3-induced apoptosis; however, further research will be required to determine the underlying details. Our findings suggest that EBF3 may act as a putative tumor suppressor gene in pediatric AML.

Molecular targeting of the oncoprotein PLK1 in pediatric acute myeloid leukemia: RO3280, a novel PLK1 inhibitor, induces apoptosis in leukemia cells.

Polo-like kinase 1 (PLK1) is highly expressed in many cancers and therefore a biomarker of transformation and potential target for the development of cancer-specific small molecule drugs. RO3280 was recently identified as a novel PLK1 inhibitor; however its therapeutic effects in leukemia treatment are still unknown. We found that the PLK1 protein was highly expressed in leukemia cell lines as well as 73.3% (11/15) of pediatric acute myeloid leukemia (AML) samples. PLK1 mRNA expression was significantly higher in AML samples compared with control samples (82.95 ± 110.28 vs. 6.36 ± 6.35; p < 0.001). Kaplan-Meier survival analysis revealed that shorter survival time correlated with high tumor PLK1 expression (p = 0.002). The 50% inhibitory concentration (IC50) of RO3280 for acute leukemia cells was between 74 and 797 nM. The IC50 of RO3280 in primary acute lymphocytic leukemia (ALL) and AML cells was between 35.49 and 110.76 nM and 52.80 and 147.50 nM, respectively. RO3280 induced apoptosis and cell cycle disorder in leukemia cells. RO3280 treatment regulated several apoptosis-associated genes. The regulation of DCC, CDKN1A, BTK, and SOCS2 was verified by western blot. These results provide insights into the potential use of RO3280 for AML therapy; however, the underlying mechanisms remain to be determined.

Zinc finger protein 382 is downregulated by promoter hypermethylation in pediatric acute myeloid leukemia patients.

Acute myeloid leukemia (AML) is the second-most common form of leukemia in children. Aberrant DNA methylation patterns are characteristic of AML. Zinc finger protein 382 (ZNF382) has been suggested to be a tumor suppressor gene possibly regulated by promoter hypermethylation in various types of human cancer. However, ZNF382 expression and methylation status in pediatric AML is unknown. In the present study, ZNF382 transcription levels were evaluated by quantitative reverse-transcription PCR. Methylation status was investigated by methylation-specific (MSP) PCR and bisulfate genomic sequencing (BGS). The prognostic significance of ZNF382 expression and promoter methylation was assessed in 105 cases of pediatric AML. The array data suggested that the ZNF382 promoter was hypermethylated in the AML cases examined. MSP PCR and BGS analysis revealed that ZNF382 was hypermethylated in leukemia cell lines. Furthermore, treatment with 5-aza-2'-deoxycytidine (5-Aza) upregulated ZNF382 expression in the selected leukemia cell lines. The aberrant methylation of ZNF382 was observed in 10% (2/20) of the control samples compared with 26.7% (28/105) of the AML samples. ZNF382 expression was significantly decreased in the 105 AML patients compared with the controls. Patients with ZNF382 methylation showed lower ZNF382 transcript levels compared with patients exhibiting no methylation. There were no significant differences in clinical characteristics or cytogenetic analysis between the patients with or without ZNF382 methylation. ZNF382 methylation correlated with minimal residual disease (MRD). Kaplan-Meier survival analysis revealed similar survival times in the samples with ZNF382 methylation, and multivariate analysis revealed that ZNF382 methylation was not an independent prognostic factor in pediatric AML. The epigenetic inactivation of ZNF382 by promoter hypermethylation can be observed in AML cell lines and pediatric AML samples. Therefore, our study suggests that ZNF382 may be considered a putative tumor suppressor gene in pediatric AML. However, further studies focusing on the mechanisms responsible for ZNF382 downregulation in pediatric leukemia are required.

Metallothionein III (MT3) is a putative tumor suppressor gene that is frequently inactivated in pediatric acute myeloid leukemia by promoter hypermethylation.

BACKGROUND: Acute myeloid leukemia (AML) is the second most common form of leukemia in children. Aberrant DNA methylation patterns are a characteristic feature in various tumors, including AML. Metallothionein III (MT3) is a tumor suppresser reported to show promoter hypermethylated in various cancers. However, the expression and molecular function of MT3 in pediatric AML is unclear. METHODS: Eleven human leukemia cell lines and 41 pediatric AML samples and 20 NBM/ITP (Norma bone marrow/Idiopathic thrombocytopenic purpura) control samples were analyzed. Transcription levels of MT3 were evaluated by semi-quantitative and real-time PCR. MT3 methylation status was determined by methylation specific PCR (MSP) and bisulfite genomic sequencing (BSG). The molecular mechanism of MT3 was investigated by apoptosis assays and PCR array analysis. RESULTS: The MT3 promoter was hypermethylated in leukemia cell lines. More CpG's methylated of MT3 was observed 39.0% pediatric AML samples compared to 10.0% NBM controls. Transcription of MT3 was also significantly decreased in AML samples compared to NBM/ITP controls (P < 0.001); patients with methylated MT3 exhibited lower levels of MT3 expression compared to those with unmethylated MT3 (P = 0.049). After transfection with MT3 lentivirus, proliferation was significantly inhibited in AML cells in a dose-dependent manner (P < 0.05). Annexin V assay showed that apoptosis was significantly upregulated MT3-overexpressing AML cells compared to controls. Real-time PCR array analysis revealed 34 dysregulated genes that may be implicated in MT3 overexpression and apoptosis in AML, including FOXO1. CONCLUSION: MT3 may be a putative tumor suppressor gene in pediatric AML. Epigenetic inactivation of MT3 via promoter hypermethylation was observed in both AML cell lines and pediatric AML samples. Overexpression of MT3 may inhibit proliferation and induce apoptosis in AML cells. FOXO1 was dysregulated in MT3-overexpressing cells, offering an insight into the mechanism of MT3-induced apoptosis. However, further research is required to determine the underlying molecular details.