Relationship between subtype-specific minimal residual disease level and long-term prognosis in children with acute lymphoblastic leukemia.

Minimal residual disease (MRD) based risk stratification criteria for specific genetic subtypes remained unclear in childhood acute lymphoblastic leukemia (ALL). Among 723 children with newly diagnosed ALL treated with the Chinese Children Leukemia Group CCLG-2008 protocol, MRD was assessed at time point 1 (TP1, at the end of induction) and TP2 (before consolidation treatment) and the MRD levels significantly differed in patients with different fusion genes or immunophenotypes (P all < 0.001). Moreover, the prognostic impact of MRD varied by distinct molecular subtypes. We stratified patients in each molecular subtype into two MRD groups based on the results. For patients carrying BCR::ABL1 or KMT2A rearrangements, we classified patients with MRD < 10-2 at both TP1 and TP2 as the low MRD group and the others as the high MRD group. ETV6::RUNX1+ patients with TP1 MRD < 10-3 and TP2 MRD-negative were classified as the low MRD group and the others as the high MRD group. For T-ALL, We defined children with TP1 MRD ≥ 10-3 as the high MRD group and the others as the low MRD group. The 10-year relapse-free survival of low MRD group was significantly better than that of high MRD group. We verified the prognostic impact of the subtype-specific MRD-based stratification in patients treated with the BCH-ALL2003 protocol. In conclusion, the subtype-specific MRD risk stratification may contribute to the precise treatment of childhood ALL.

Low expression of CTBP2 and CASP8AP2 predicts risk of relapse in childhood B-cell precursor acute lymphoblastic leukemia: a retrospective cohort study.

CtBP is a known corepressor abundantly expressed in cancer and regulates genes involved in cancer initiation, progression, and metastasis. This study aimed to investigate the prognostic significance of CTBP2 expression in a cohort of pediatric patients with B cell precursor acute lymphoblastic leukemia (BCP-ALL). It further evaluated the role of combined CTBP2 and CASP8AP2 expression in risk of relapse of BCP-ALL. The expression of CTBP2 mRNA was retrospectively detected by a qRT-PCR approach in bone marrow samples from 104 children with newly diagnosed BCP-ALL. CASP8AP2 was assessed simultaneously in the 100 patients included in this study. The receiver operating characteristic (ROC) curve analysis determined the cut off levels for CTBP2 and CASP8AP2 expression with good predictive significance for relapse of BCP-ALL. Patients with low CTBP2 expression had inferior relapse-free survival (RFS) and event-free survival (EFS) when compared to patients with high-CTBP2 expression. The expression level of CTBP2 was significantly associated with CASP8AP2 expression (r = 0.449, P < 0.001). Patients were stratified into three groups according to the combined evaluation of the two gene expression, and patients with simultaneous low-expression had the worst outcome (6-year RFS: 64.6%±12.8%, P < 0.001). Multivariate analysis demonstrated the expression of CTBP2 and CASP8AP2, minimal residual disease (MRD) at day 33 remained as independent prognostic factors for RFS. Based on the final Cox hazards model, we proposed an algorithm to calculate the risk index, which was more precise for predicting relapse. In conclusion, low expression of CTBP2 and CASP8AP2 correlated with poor outcome and predicted risk of relapse in pediatric BCP-ALL.

Transcription factor E2F3a regulates CASP8AP2 transcription and enhances sensitivity to chemotherapeutic drugs in acute lymphoblastic leukemia.

BACKGROUND: Low expression of E2F3a and caspase 8 associated protein 2 (CASP8AP2) are associated with poor prognosis of childhood acute lymphoblastic leukemia (ALL). METHODS: Dual-luciferase reporter assay and wild type as well as four mutated types of reporter plasmids were used to demonstrate the activation of E2F3a on CASP8AP2 transcription. The direct binding of E2F3a with the promoter of CASP8AP2 was shown by Chromatin Immunoprecipitation (ChIP). Cell proliferation activity and cell cycle were determined by MTS and flow cytometry in leukemic cells after treating with common chemotherapeutic drugs vincristine and daunorubicin. RESULTS: In this study, we found that up-regulation of E2F3a in leukemic cells led to increased fraction of cells in S and G2/M phase, accelerated proliferation, and enhanced sensitivity to vincristine and daunorubicin. ChIP and luciferase assay indicated that E2F3a could directly bind to two fragments in the wild type of CASP8AP2 promotor (- 206 to - 69 and - 677 to - 507), and activate its transcription activity which was reduced in mutated promotors. The effect of E2F3a on chemotherapeutic sensitivity of leukemic cells could be reversed by down-regulating CASP8AP2. CONCLUSIONS: E2F3a could promote transcription and expression of CASP8AP2. The effect of E2F3a on chemotherapeutic sensitivity of ALL cells was implemented by regulating CASP8AP2 expression to a great extent.

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.

NOTCH1 mutations are associated with favourable long-term prognosis in paediatric T-cell acute lymphoblastic leukaemia: a retrospective study of patients treated on BCH-2003 and CCLG-2008 protocol in China.

Activating mutations of NOTCH1 are a common occurrence in T-cell acute lymphoblastic leukaemia (T-ALL), but its impact on T-ALL treatment is still controversial. In this study, the incidence, clinical features, and prognosis of 92 Chinese children with T-ALL treated using the Beijing Children's Hospital-2003 and Chinese Childhood Leukaemia Group-2008 protocols were analysed. NOTCH1 mutations were found in 42% of T-ALL patients and were not associated with clinical features, prednisone response, and minimal residual disease (MRD) at day 33 and 78. However, proline, glutamate, serine, threonine (PEST)/transactivation domain (TAD) mutations were associated with younger age (15/16 mutant vs. 48/76 wild-type, P = 0·018) and more central nervous system involvement (4/16 mutant vs. 3/76 wild-type, P = 0·016); while heterodimerization domain (HD) mutations were associated with KMT2A-MLLT1 (MLL-ENL; 4/30 mutant vs. 1/62 wild-type, P = 0·037). Furthermore, prognosis was better in patients with NOTCH1 mutations than in those with wild-type NOTCH1 (5-year event-free survival [EFS] 92·0 ± 4·5% vs. 64·0 ± 7·1%; P = 0·003). Long-term outcome was better in patients carrying HD mutations than in patients with wild-type HD (5-year EFS 89·7 ± 5·6% vs. 69·3 ± 6·2%; P = 0·034). NOTCH1 mutations and MRD at day 78 were independent prognostic factors. These findings indicate that NOTCH1 mutation predicts a favourable outcome in Chinese paediatric patients with T-ALL on the BCH-2003 and CCLG-2008 protocols, and may be considered a prognostic stratification factor.

E2F3a gene expression has prognostic significance in childhood acute lymphoblastic leukemia.

OBJECTIVES: To study E2F3a expression and its clinical significance in children with acute lymphoblastic leukemia (ALL). METHODS: We quantified E2F3a expression at diagnosis in 148 children with ALL by real-time PCR. In the test cohort (n = 48), receiver operating characteristic (ROC) curve was used to find the best cut-off point to divide the patients into E2F3a low- and high-expression groups. The prognostic significance of E2F3a expression was investigated in the test cohort and confirmed in the validation cohort (n = 100). The correlations of E2F3a expression with the clinical features and treatment outcome of these patients were analyzed. RESULTS: ROC curve analysis indicated that the best cut-off point of E2F3a expression was 0.3780. In the test cohort, leukemia-free survival (LFS) and event-free survival (EFS) of the low-expression group were lower than those of the high-expression group (log rank: P = 0.026 for both). This finding was verified in the validation cohort. LFS, EFS, and overall survival were also lower in the low-expression group than in the high-expression group (log rank, P = 0.015, 0.008, and 0.002 respectively). E2F3a low expression was correlated with the existence of BCR-ABL fusion. An algorithm composed of E2F3a expression and minimal residual disease (MRD) could predict relapse or induction failure more precisely than current risk stratification. These results were still significant in the ALL patients without BCR-ABL fusion. CONCLUSIONS: Low expression of E2F3a was associated with inferior prognosis in childhood ALL. An algorithm composed of E2F3a expression and MRD could predict relapse or induction failure more precisely than that of the current risk stratification.

FPGS rs1544105 polymorphism is associated with treatment outcome in pediatric B-cell precursor acute lymphoblastic leukemia.

BACKGROUND: Folypolyglutamate synthase (FPGS) catalyzes the polyglutamation of folates and antifolates, such as methotrexate (MTX), to produce highly active metabolites. FPGS tag SNP rs1544105C > T is located in the gene promoter. The aim of the present study was to investigate the impact of rs1544105 polymorphism on the treatment outcome in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). METHODS: This study enrolled 164 children with BCP-ALL. We genotyped the FPGS SNP rs1544105, and analyzed the associations between its genotypes and treatment outcome. We also examined FPGS mRNA levels by real-time PCR in 64 of the 164 children, and investigated the function of this polymorphism on gene expression. RESULTS: We found significantly poor relapse-free survival (RFS) (p = 0.010) and poor event-free survival (EFS) (p = 0.046) in carriers of CC genotype. Multivariable Cox regression analyses adjusted for possible confounding variables showed that, relative to the CT + TT genotypes, the CC genotype was an independent prognostic factor for poor RFS (hazard ratio [HR], 4.992.; 95% CI, 1.550-16.078; p = 0.007). No association was found between any toxicity and rs1544105 polymorphism. Quantitative PCR results showed that individuals with the T allele had lower levels of FPGS transcripts. CONCLUSIONS: Our study indicates that FPGS rs1544105C > T polymorphism might influence FPGS expression and affect treatment outcome in BCP-ALL patients.

Clinical features, early treatment responses, and outcomes of pediatric acute lymphoblastic leukemia in China with or without specific fusion transcripts: a single institutional study of 1,004 patients.

Acute lymphoblastic leukemia (ALL) with distinct fusion transcripts has unique clinical features. In this study, the incidence, clinical characteristics, early treatment response, and outcomes of 1,004 Chinese pediatric ALLs were analyzed. Patients with TEL-AML1 and E2A-PBX1 fusion genes or other B cell precursor ALLs (BCP-ALL) had favorable clinical features, were sensitive to prednisone, had low minimal residual disease (MRD), and an excellent prognosis, with a 5-year event-free survival (EFS) of 84-92%. T-ALL was associated with a high WBC, increased age, more central nervous system involvement, a poor prednisone response, and high MRD, with a 5-year EFS of 68.4 ± 5.2%. Patients with BCR-ABL and MLL rearrangements usually had adverse clinical presentations and treatment responses, and a dismal prognosis, with 5-year EFS of 27.3 and 57.4%, respectively. We also showed that BCR-ABL and MLL rearrangements, the prednisone response, and MRD were independent prognostic factors. Interestingly, the BCH-2003 protocol resulted in a better outcome for E2A-PBX1(+) patients than the CCLG-2008 protocol. Intermediate and late relapses were more common in TEL-AML1(+) patients and other BCP-ALLs compared with other subgroups (P = 0.018). Therefore, this study suggests that a fusion gene-specific chemotherapy regimen and/or targeted therapy should be developed to improve further the cure rate of pediatric ALL.

Polymorphisms in methotrexate transporters and their relationship to plasma methotrexate levels, toxicity of high-dose methotrexate, and outcome of pediatric acute lymphoblastic leukemia.

High-dose methotrexate (HDMTX) plays an important role in the treatment of acute lymphoblastic leukemia (ALL) although there is great inter-patient variability in the efficacy and toxicity of MTX. The relationship between polymorphisms in genes encoding MTX transporters and MTX response is controversial. In the present study, 322 Chinese children with standard- and intermediate-risk ALL were genotyped for 12 polymorphisms. SLCO1B1 rs10841753 showed a significant association with plasma MTX levels at 48 h (P = 0.017). Patients who had the ABCB1 rs1128503 C allele had longer duration of hospitalization than did those with the TT genotype (P = 0.006). No association was found between oral mucositis and any polymorphism. Long-term outcome was worse in patients with the SLCO1B1 rs4149056 CC genotype than in patients with TT or TC (5-year event-free survival [EFS] 33.3 ± 19.2% vs. 90.5 ± 1.7%, P < 0.001), and was worse in patients with the SCL19A1 rs2838958 AA genotype than in patients with AG or GG (5-year EFS 78.5 ± 4.6% vs. 92.2 ± 1.8%, P = 0.008). Multiple Cox regression analyses revealed associations of minimal residual disease (MRD) at day 33 (hazard ratio 3.458; P = 0.002), MRD at day 78 (hazard ratio 6.330; P = 0.001), SLCO1B1 rs4149056 (hazard ratio 12.242; P < 0.001), and SCL19A1 rs2838958 (hazard ratio 2.324; P = 0.019) with EFS. Our findings show that polymorphisms in genes encoding MTX transporters substantially influence the kinetics and response to HDMTX therapy in childhood ALL.

[Relationships between thiopurine methyltransferase gene polymorphisms and its enzymatic activity].

OBJECTIVE: To investigate the relationship between the thiopurine methytransferase (TPMT) gene polymorphisms and its enzymatic activity, and to clarify the significance of TPMT activity and gene polymorphisms on individualized therapy with thiopurines. METHODS: The TPMT activity and gene polymorphisms were determined in an unrelated population of 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia. The TPMT genotyping assay was based on polymerase chain reaction (PCR), restriction digestion of PCR products, denaturing high-performance liquid chromatography (DHPLC) and SNaPshot sequencing and direct DNA sequencing in the TPMT exon 5 (G238C), TPMT exon7 (G460A) and TPMTexon10 (A719G). Erythrocyte TPMT activity was measured by high-performance liquid chromatography (HPLC). RESULTS: The frequency of TPMT polymorphism in 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia was low (3.5%), and all the varied alleles were TPMT* 3C (exon 10A719G). All of them were TPMT* 1/TPMT* 3C heterozygote. The TPMT activity was between 6 and 12 U. The activity in 95.1% was more than 12 U (13 - 32 U), while the activity in others (4.9%) was 6 - 12 U. TPMT activity and genotype were concordant. Of 630 subjects evaluated, TPMT activity of heterozygous individuals in Chinese healthy blood donors, cords blood and acute leukemia patients were 9.1 U, 9.3 U and 9.07 U, respectively, significantly lower than that in general population (17.6 U, 17.67 U and 18.6 U, respectively). In the samples analyzed, ten subjects with heterozygous phenotypes (6/15 acute leukemia children and 4/16 healthy blood donors and cords blood) did not have TPMT* 2, TPMT* 3A or TPMT* 3C. Therefore, other factors may affect on TPMT activity. CONCLUSION: TPMT gene polymorphisms and its activity were concordant. The heterozygotes had low TPMT activity. Therefore, detection of TPMT genotype and its activity is useful. These findings hold a promise of improving the safety and efficacy of thiopurines therapy.

[Clinical Characteristics and Treatment Efficacy of Children with SIL/TAL1 Positive T-Cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To investigate the clinical features, treatment and prognosis of children with SIL-TAL1 fusion gene positive T-cell acute lymphoblastic leukemia (T-ALL). METHODS: The data of 101 children with T-ALL were collected from April 2005 to November 2012 in Beijing Children's Hospital. The common clinical features, early treatment response, minimal residual disease (MRD), event-free survival (EFS) and relapse-free survival (RFS) were compared between children with SIL-TAL1 positive and negative T-ALL. The treatment efficacy in children with SIL-TAL1 positive T-ALL was compared between BCH-2003 and CCLG-2008 protocol. RESULTS: Out of 101 cases, 22 cases (21.9%) of T-ALL carried SIL-TAL1 fusion gene. The distribution of sex, age, response to prednisone and central nervous system (CNS) involvement were no significant different at diagnosis between SIL-TAL1 positive and negetive patients. However, the WBC count in SIL-TAL1 positive cases were significantly higher than that of SIL-TAL1 negative cases at diagnosis (P<0.05). Additionally, MRD levels were not significantly different between children with SIL-TAL1 positive or negative T-ALL at 3 time points including: after the remission induction therapy, before delayed intensive therapy II and before maintenance therapy. However, the number of cases with high MRD levels before consolidation therapy were more in SIL-TAL1 positive group than that in SIL-TAL1 negative group (P<0.05). The cases with high MRD levels before delayed intensive therapy I was more in SIL-TAL1 negative group than that in the SIL-TAL1 positive group (P>0.05). Besides, there were no significant differences in 5-year EFS and RFS between the two groups. The risk of 22 children with SIL-TAL1 positive acute T-ALL was again stratified according to the typing stemdard in CCLG-2008 protocol, as a result, the risk in BCH-2003 group (10 cases) was significantly higher than that in BCH-2008 group (12 cases) (P<0.05), but no significant difference was found in common clinical features, early treatment response, MRD levels and treatment efficacy. CONCLUSIONS: Although WBC level was significantly higher in SIL-TAL1 positive group than that in SIL-TAL1 negative group, the treatment efficacy in SIL-TAL1 positive group was similar to SIL-TAL1 negative group. Meanwhile, the children with SIL-TAL1+ T-ALL may respond poorly to early intensive therapy, the BCH-2003 protocol may be more suitable for the patients with this subtype of leukemia.

[Research Progress on Expression Regulation, Function and Clinical Significance of CASP8AP2 Gene].

We systematically reviewed the results of the studies on expression regulation, biological functions, and clinical prognostic significance of CASP8AP2 gene. At present, the studies showed that the expression of CASP8AP2 gene was regulated by Homeobox proteins and DNA methylation, and could be silenced by miRNA-210. This protein was involved in apoptosis mediated by FAS and TNFα, NF-κB activation mediated by TNFα, regulation of gene expression induced by glucocorticoid and mineralocorticoid receptor, comprising Cajal body and histone locus body, transcription of replication-dependent histone, 3' end processing of histone, regulation of S phase progression, in addition to functioning as coactivator of transcription factors c-Myb and p73 to activating many genes' expression. On the other hand, low expression of CASP8AP2 gene was associated with relapse in childhood ALL. The deletion of this gene was related to the poor prognosis of children with T-ALL and T lymphoblastic lymphoma. Furthermore, 3 SNPs in this gene were possibly correlated with genesis of diffuse large B cell lymphoma and childhood leukemia. In conclusions, CASP8AP2 was a multifunctional protein. It could function to regulate cell proliferation, apoptosis, and gene expression. In childhood hematological malignancies, CASP8AP2 was a promising molecular marker with prognostic significance. Some SNPs were possibly correlated with leukemo- and lymphomogenesis.

[Clinical significance of CASP8AP2 gene methylation in childhood acute lymphoblastic leukemia].

OBJECTIVE: To study the methylation level in the promoter of caspase 8 associated protein 2 (CASP8AP2) gene between samples at diagnosis and in complete remission, and to investigate its relationship with clinical features and prognosis in children with acute lymphoblastic leukemia (ALL). METHODS: Diagnostic DNA samples from 109 newly diagnosed children with ALL admitted from August 2007 to March 2010, and 94 ALL children in CR (complete remission) among them were collected. Bisulfite modification and MethyLight method established by our research team were used to determine the methylation level of the two key CpG sites (at -1189 and -1176) of the promoter of CASP8AP2 gene. RESULTS: The average methylation level of the two CpG sites in newly diagnosted samples was higher than that in CR samples (71.1% ± 1.7% vs 64.2% ± 21.2%) (P = 0.008). Analysis with receiver operating characteristic (ROC) curve showed that the area under curve was 0.687 (P = 0.024), indicating that the methylation level of the two CpG sites was able to predict relapse efficiently to some extent, 76.9% was chosed as a cutoff value to divide the patients into high methylation group (49 patients) and low methylation group (60 patients). The incidence of relapse in high methylation group was higher than that in low methylation group (20.4% vs 6.7%) (P = 0.044), five year relapse free survival in high methylation group was also lower than that in low methylation group (Log rank, P = 0.033). Furthermore, high methylation at new diagnosis were correlated with high level of minimal residual disease (MRD) before consolidation therapy (P = 0.011). In the 34 children with MRD ≥ 10(-4) at the end of induction remission, the relapse rate of high methylation patients was significantly higher than that of low methylation patients (8/16 vs 3/18)(P = 0.038). CONCLUSION: The abnormal hypermethylation of the two CpG sites (at -1189 and -1176) of the promoter of the CASP8AP2 gene is possibly associated with leukemogenesis in childhood ALL. The treatment outcome is more poor in patients with hypermethylation than that in patients with low methylation. The combination of the methylation level of the two CpG sites and MRD level at the end induction remission is able to predict relapse more effectively.

Low expressions of ARS2 and CASP8AP2 predict relapse and poor prognosis in pediatric acute lymphoblastic leukemia patients treated on China CCLG-ALL 2008 protocol.

ARS2 protein is important to early development and cell proliferation, in which ARS2-CASP8AP2 interaction is implicated. However, the predictive significance of ARS2 in childhood acute lymphoblastic leukemia (ALL) is unknown. Here we evaluate the predictive values of ARS2 expression and combined ARS2 and CASP8AP2 expression in relapse. We showed that ARS2 expression in ALL bone marrow samples at initial diagnosis was markedly lower than that in complete remission (CR). Likewise, the levels of ARS2 expression in the patients suffering from relapse were significantly lower than that of patients in continuous CR. Furthermore, low expression of ARS2 was closely correlated to poor treatment response including poor prednisone response and high minimal residual disease (MRD), and the patients with high MRD (≥10(-4)) and low ARS2 were more subject to relapse. The multivariate analyses for relapse free survival and event free survival revealed that ARS2 expression remained an independent prognostic factor after adjusting other risk factors. In addition, combined assessment of ARS2 and CASP8AP2 expression was more accurate to predict relapse, based on which an algorithm composed of ARS2 and CASP8AP2 expression, prednisone response and MRD (day 78) was proposed. Together, ARS2 and CASP8AP2 expressions can precisely predict high-risk of relapse and ALL prognosis.

Infections during induction therapy of protocol CCLG-2008 in childhood acute lymphoblastic leukemia: a single-center experience with 256 cases in China.

BACKGROUND: Infections remain a major cause of therapy-associated morbidity and mortality in children with acute lymphoblastic leukemia (ALL). METHODS: We retrospectively analyzed the medical charts of 256 children treated for ALL under the CCLG-2008 protocol in Beijing Children's Hospital. RESULTS: There were 65 infectious complications in 50 patients during vincristine, daunorubicin, L-asparaginase and dexamethasone induction therapy, including microbiologically documented infections (n = 12; 18.5%), clinically documented infections (n = 23; 35.3%) and fever of unknown origin (n = 30; 46.2%). Neutropenia was present in 83.1% of the infectious episodes. In all, most infections occurred around the 15 th day of induction treatment (n = 28), and no patients died of infection-associated complications. CONCLUSIONS: The infections in this study was independent of treatment response, minimal residual diseases at the end of induction therapy, gender, immunophenotype, infection at first visit, risk stratification at diagnosis, unfavorable karyotypes at diagnosis and morphologic type. The infection rate of CCLG-2008 induction therapy is low, and the outcome of patients is favorable.

[Correlation analysis of FPGS rs10760502G>a polymorphism with prognosis and MTX-related toxicity in pediatric B-cell acute lymphoblastic leukemia].

This study was aimed to explore the relation between folylpolyglutamate synthetase (FPGS) rs10760502 polymorphism and prognosis and methotrexate (MTX)-related toxicities in pediatric B-cell acute lymphoblastic leukemia (B-ALL). Sequenom MassARRAY was used to genotype rs10760502. The χ(2) test, Kaplan-Meier method and Cox regression models were used to analyze the data. The results indicated that A allele carriers (GA+AA) had poor relapse free survival (RFS, log-rank: P = 0.004) and event free survival (EFS, log-rank: P = 0.022) compared with the GG genotype carriers. Multivariate Cox-regression analysis results showed that A allele is an independent prognosis factor for poor RFS [hazard ratio (HR), 20.173; 95% CI, 2.535-160.545; P = 0.005] and EFS (HR, 8.133; 95% CI, 1.718-38.512; P = 0.008). No relationship was found between any MTX toxicity and rs10760502 polymorphism. It is concluded that FPGS rs10760502G>A polymorphism may affect the treatment outcome of B-ALL patients.

[Evaluation of early response to treatment and its prognostic value in childhood acute lymphoblastic leukemia].

This study was purposed to investigate the prognostic value of early response to treatment in childhood acute lymphoblastic leukemia (ALL). Four indexes were used to assess early response to treatment including response to prednisone on day 8 (D8-PR), percentage of lymphoblast in bone marrow on day 22 (D22-BM) and day 33 (D33-BM), the level of minimal residual disease (MRD) on day 33 (D33-MRD) by morphological and molecular biological method in 426 children with ALL. Prognostic impact of early response to treatment was analyzed, and multivariate analysis of the predictive value was performed by Cox-regression analysis. All patients were followed up until October 31, 2013, with a median follow-up time of 80 months (0.5 to 106 months). The results showed that there were significant differences between event free survivals (EFS) of the sub-groups divided according to the four indexes. The 8 years-EFS in patients with prednisone good response (PGR) was significantly higher than that in patients with prednisone poor response (PPR);patients with M1 in bone marrow on day 22 or day 33 had the better outcomes than that of patients with M2/M3;patients with high level of MRD ( ≥ 10(-4)) had the worse outcomes as compared with patients with low level of MRD (<10(-4)) (P < 0.001). Cox proportional hazard model analysis showed that BCR/ABL fusion gene positive, D8-PR, D33-BM and D33-MRD were the independent prognostic factors for childhood ALL, and the hazard ratio of D33-MRD ≥ 10(-2) was highest (HR:11.886, P < 0.001). It is concluded that early response to treatment is an independent prognostic factor with important prognostic values, and it has important clinical guiding instructive significance for risk stratification in the treatment of children ALL.

[Comparison of the efficacy of two chemotherapy protocols for children with TEL-AML1[STBZ] fusion gene positive acute lymphoblastic leukemia].

This study was aimed to compare the curative effect of BCH - 2003 protocol and CCLG - 2008 protocol for children with TEL-AML1 fusion gene positive childhood acute lymphoblastic leukemia (ALL) and to investigate the more suitable protocol for this subtype of childhood leukemia. The clinical data for children with TEL-AML1 fusion gene positive ALL admitted from January 2003 to October 2010 in Hematology Center of Beijing Children's Hospital were collected. The common clinical characteristics including prednisone response at day 8, minimal residual disease (MRD) at the end of induction of remission (day 33), event free survival (EFS), relapse free survival (RFS) were compared. The results showed that out of 204 children with TEL-AML1 fusion gene positive ALL, 134 and 70 patients were treated by BCH-2003 protocol and CCLG-2008 protocol respectively. There were no statistical difference in age, white blood cell count in peripheral blood at presentation, prednisone response and CNS involvement. However, there were more boys in CCLG-2008 group (P = 0.025). The negative rate of MRD at day 33 in BCH-2003 group was lower than that in CCLG-2008 group (P = 0.013). After re-stratifying the patients in CCLG-2008 group according to the stratification criteria of BCH-2003 protocol, the negative rate of MRD at day 33 of patients with intermediate risk remained higher in BCH-2003 group than that in CCLG-2008 group (P = 0.014) . However, no significant difference in the patients with standard risk was found. There were also no significant statistical differences in the incidence of severe infection, EFS and RFS, (P = 1.000, P = 0.327,P = 0.251 respectively) during chemotherapy. It is concluded that for children with TEL-AML1 fusion gene positive ALL, the induction of remission of BCH - 2003 protocol can decrease leukemic load more quickly than that of CCLG - 2008 protocol. However, the outcome of the patients treated by the two protocols is similar.

Hypermethylation of two CpG sites upstream of CASP8AP2 promoter influences gene expression and treatment outcome in childhood acute lymphoblastic leukemia.

DNA hypermethylation of Caspase 8 associated protein 2 (CASP8AP2) and its role in childhood acute lymphoblastic leukemia (ALL) is unclear. We analyzed methylation status of CpG sites upstream of CASP8AP2 gene in 86 children with ALL by bisulfite sequencing and quantitative PCR. Methylation percentage of two CpG sites at positions of -1189 and -1176 was inversely correlated with mRNA expression (Spearman correlation: -0.333, P=0.002). High methylation was associated with the existence of minimal residual disease (MRD) at day 78 (P=0.035), The patients in high methylation group had a poor treatment outcome. The combination of methylation level and MRD at day 33 might improve current risk stratification.