Minyuan Wu

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. Am. J. Hematol. 2012.

Gene expression-based classification and regulatory networks of pediatric acute lymphoblastic leukemia

Pediatric acute lymphoblastic leukemia (ALL) contains cytogenetically distinct subtypes that respond differently to cytotoxic drugs. Subtype classification can be also achieved through gene expression profiling. However, how to apply such classifiers to a single patient and correctly diagnose the disease subtype in an independent patient group has not been addressed. Furthermore, the underlying regulatory mechanisms responsible for the subtype-specific gene expression patterns are still largely unknown. Here, by combining 3 published microarray datasets on 535 mostly white childrens samples and generating a new dataset on 100 Chinese childrens ALL samples, we were able to (1) identify a 62-gene classifier with 97.6% accuracy from the white childrens samples and validated it on the completely independent set of 100 Chinese samples, and (2) uncover potential regulatory networks of ALL subtypes. The classifier we identified was, thus far, the only one that could be applied directly to a single sample and that sustained validation in a large independent patient group. Our results also suggest that the etiology of ALL is largely the same among different ethnic groups, and that the transcription factor hubs in the predicted regulatory network might play important roles in regulating gene expression and development of ALL.

Effect of microRNA-210 on prognosis and response to chemotherapeutic drugs in pediatric acute lymphoblastic leukemia

Many studies have demonstrated that microRNA‐210 (miR‐210) expression is intensively upregulated in hypoxic states and differentially regulated in most types of cancer cells. However, the clinical significance of miR‐210 and its effects on the response of leukemic cells to chemotherapeutic drugs in childhood acute lymphoblastic leukemia (ALL) remain unknown. In the current study, using real‐time qRT‐PCR to detect miR‐210 expression in bone marrow samples from 114 children at initial diagnosis of ALL, we investigated the prognostic significance of miR‐210 and determined its associations with common clinical characteristics and treatment outcome. We further examined its effect on the response to chemotherapeutic drugs in the Reh and RS4;11 cell lines. Results showed that miR‐210 expression was significantly lower in patients suffering from relapse and induction failure than in other patients (P < 0.001). Using the receiver operating characteristic curve, 3.8243 was selected as the cut‐off value of miR‐210 expression in our test cohort (38 cases). A significantly poorer treatment outcome (P < 0.05) was found in the low‐expression group and verified in the validation cohort (76 cases, P < 0.05). Patients with low expression of miR‐210 and positive minimal residual disease at the end of induction had a much higher rate of relapse or induction failure (P = 0.001). Increasing/decreasing miR‐210 expression using agomir/antagomir could enhance or reduce the response of Reh cells and RS4;11 cells to daunorubicin/dexamethasone/L‐asparaginase and daunorubicin/dexamethasone/vincristine, respectively. In conclusion, miR‐210 may be a good prognostic factor and a useful predictor of drug sensitivity, and is a potential therapeutic target for pediatric ALL.

CASP8AP2 is a promising prognostic indicator in pediatric acute lymphoblastic leukemia

The prognostic significance of caspase 8 associated protein 2 (CASP8AP2) in pediatric ALL is controversial. We determined a cut-off of CASP8AP2 expression in bone marrow samples of 39 newly diagnosed patients, and found a significantly poor bone marrow relapse-free survival (p=0.019) in low-expression group and verified it in another cohort of 106 patients (p=0.002). Furthermore, as an independent prognostic factor, CASP8AP2 expression was correlated to minimal residual disease (MRD), and incorporating it with MRD would help to identify patients at greater risk of bone marrow relapse. We also developed an algorithm comprised of clinical risk and CASP8AP2 expression, which could predict bone marrow relapse more accurately.

Combined analysis of minimal residual disease at two time points and its value for risk stratification in childhood B-lineage acute lymphoblastic leukemia

The study was aimed to explore the value of minimal residual disease (MRD) for risk stratification in childhood precursor-B-acute lymphoblastic leukemia. MRD was monitored at two time points (TP1, after induction and TP2, before consolidation therapy) by quantitative detection of monoclonal immunoglobulin heavy chain gene rearrangements. This study stratified 105 patients into three MRD risk groups: standard-risk, MRD<10(-4) at both TP1 and TP2; high-risk, TP1>or=10(-2) or TP2>or=10(-3); and others were classified as intermediate-risk. We incorporated this MRD risk information to refine risk stratification among these patients and developed a new classification system that predicted the treatment outcomes more successfully than did the traditional risk classification criteria.

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

BackgroundFolypolyglutamate 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).MethodsThis 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.ResultsWe 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.ConclusionsOur study indicates that FPGS rs1544105C > T polymorphism might influence FPGS expression and affect treatment outcome in BCP-ALL patients.

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 Childrens 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.

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.

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 Childrens 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 15th 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.