Genomics of next generation sequencing in pediatric B-acute lymphoblastic leukemia and its impact on minimal residual disease / 中华儿科杂志

Objective: To describe the gene mutation profile of newly diagnosed pediatric B-acute lymphoblastic leukemia (B-ALL) and analyze its effect on minimal residual disease (MRD). Methods: A total of 506 newly diagnosed B-ALL children treated in Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences from September 2018 to July 2021 were enrolled in this retrospective cohort study. The enrolled children were divided into MRD ≥1.00% group and <1.00% group according to MRD results on the 19th day since chemotherapy, and MRD ≥0.01% group and <0.01% group according to MRD results on the 46th day. Clinical characteristics and gene mutations of two groups were compared. Comparisons between groups were performed with chi-square test or Fisher's exact test. Independent risk factors of MRD results on the 19th day and the 46th day were analyzed by Logistic regression model. Results: Among all 506 patients, there were 318 males and 188 females. On the 19th day, there were 114 patients in the MRD ≥1.00% group and 392 patients in the MRD <1.00% group. On the 46th day, there were 76 patients in the MRD ≥0.01% group and 430 patients in the MRD <0.01% group. A total of 187 gene mutations were detected in 487 (96.2%) of 506 children. The most common gene mutations were signal transduction-related KRAS gene mutations in 111 cases (22.8%) and NRAS gene mutations in 99 cases (20.3%). Multivariate analysis showed that PTPN11 (OR=1.92, 95%CI 1.00-3.63), KMT2A (OR=3.51, 95%CI 1.07-11.50) gene mutations and TEL-AML1 (OR=0.48, 95%CI 0.27-0.87), BCR-ABL1 (OR=0.27, 95%CI 0.08-0.92) fusion genes and age >10 years (OR=1.91, 95%CI 1.12-3.24) were independent influencing factors for MRD ≥1.00% on the 19th day. BCORL1 (OR=2.96, 95%CI 1.18-7.44), JAK2 (OR=2.99, 95%CI 1.07-8.42) and JAK3 (OR=4.83, 95%CI 1.50-15.60) gene mutations and TEL-AML1 (OR=0.43, 95%CI 0.21-0.87) fusion gene were independent influencing factors for MRD ≥0.01% on the 46th day. Conclusions: Children with B-ALL are prone to genetic mutations, with abnormalities in the RAS signaling pathway being the most common. Signal transduction related PTPN11, JAK2 and JAK3 gene mutations, epigenetic related KMT2A gene mutation and transcription factor related BCORL1 gene mutation are independent risk factors for MRD.

The Correlation of Minimal Residual Disease with Prognosis in TCF3-PBX1 / 中国实验血液学杂志

OBJECTIVE@#To investigate the consistency between FCM and PCR on the detecting of MRD in TCF3-PBX1@*METHODS@#55 cases of paediatric TCF3-PBX1@*RESULTS@#Among the 55 children with TCF3-PBX1@*CONCLUSION@#The detection result of MRD in TCF3-PBX1 detect by FCM and PCR shows better consistency. MRD positivity detected by FCM at the end of induction therapy (day 33) predicts a high risk of relapse in TCF3-PBX1 ALL patients.

Pharmacokinetics and pharmacodynamics of pegylated recombinant human granulocyte colony-stimulating factor in children with acute lymphoblastic leukemia: a prospective control trial / 中国当代儿科杂志

OBJECTIVE@#To study the pharmacokinetic characteristics, clinical effect, and safety of pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) in children with acute lymphoblastic leukemia (ALL).@*METHODS@#A prospective study was performed on children with ALL who cyclophosphamide, cytarabine, and 6-mercaptopurine were used for consolidation therapy. PEG-rhG-CSF (PEG-rhG-CSF group) or rhG-CSF (rhG-CSF group) was injected after chemotherapy. The plasma concentration of PEG-rhG-CSF was measured, and clinical outcome and safety were observed for both groups.@*RESULTS@#A total of 17 children with ALL were enrolled, with 9 children in the PEG-rhG-CSF group and 8 children in the rhG-CSF group. In the PEG-rhG-CSF group, the peak concentration of PEG-rhG-CSF was 348.2 ng/mL (range 114.7-552.0 ng/mL), the time to peak was 48 hours (range 12-72 hours), and the half life was 14.1 hours (range 11.1-18.1 hours). The plasma concentration curve of PEG-rhG-CSF was consistent with the mechanism of neutrophil-mediated clearance. Compared with the rhG-CSF group, the PEG-rhG-CSF group had a significantly shorter median time to absolute neutrophil count (ANC) recovery (P0.05).@*CONCLUSIONS@#The pharmacokinetic characteristics of PEG-rhG-CSF in children with ALL receiving consolidation chemotherapy are consistent with the mechanism of neutrophil-mediated clearance, with a short half life and fast recovery of ANC, and there are no significant differences in safety between PEG-rhG-CSF and rhG-CSF.

The Outcome of Severe Aplastic Anemia Children Treated with Reduced Dose of Cyclophosphamide Combined Cyclosporine A / 中国实验血液学杂志

OBJECTIVE@#To analyze the clinical efficacy and side effects of reduced-dose of cyclophosphamide combined cyclosporine A for severe aplastic anemia(SAA) children.@*METHODS@#Ten pediatric patients with SAA from January 2008 to May 2012 were enrolled. All the patients were treated with reduced dose of cyclophosphamide combined cyclosporine A. The dose of cyclophosphamide was 30 mg/(kg·d)×4 d, the dose of cyclosporine A gradually increased >15 mg/L accroding to the blood concentration.@*RESULTS@#The median follow-up time of the 10 pediatric patients was 100 months (6-126 months). Among 10 children with SAA, 4 cases achieved complete response(CR), 3 cases obtained partial response (PR) and the overall response rate was 70%, the remaining 3 cases showed no response (NR). One refractory patient treated by cyclophosphamide was progressed to paroxysmal nocturnal hemoglobinuria(PNH) at 25 months and was dead at 42 months after therapy.@*CONCLUSION@#The results show that reduced-dose cyclophosphamide (30 mg/kg·d for 4 consecutive days) combinated with CsA (initial dose 4 mg/kg·d, and drugvallery concentration >150 ng/ml) can make 7 of 10 children with severe aplastic anemia achieve complete response or partial response, and this regimen may be the second line regimen selected for some SAA children.

Clinical features and prognosis of children with acute lymphoblastic leukemia and different platelet levels / 中国当代儿科杂志

OBJECTIVE@#To study the association of platelet level at diagnosis with prognosis in children with acute lymphoblastic leukemia (ALL).@*METHODS@#A total of 892 children with ALL who underwent chemotherapy with the CCLG-ALL 2008 regimen were enrolled. According to the platelet count at diagnosis, these children were divided into normal platelet count group (platelet count ≥100×109/L; n=263) and thrombocytopenia group (platelet count 0.05). The normal platelet count group still had a significantly higher 10-year EFS rate than the thrombocytopenia group after the children with MLL gene rearrangement were excluded (P0.05). The <20×10/L subgroup had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50- <100)×10/L subgroup, and the (20- <50)×10/L subgroup (P<0.05). After the children with MLL gene rearrangement were excluded, the <20×10/L subgroup still had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50-<100)×10/L subgroup, and the (20- <50)×10/L subgroup (P<0.05).@*CONCLUSIONS@#ALL children with MLL gene rearrangement often have the clinical manifestation of thrombocytopenia. Platelet level at diagnosis is associated with the prognosis of ALL children. The children with normal platelet count have a low recurrence rate and good prognosis, and those with a platelet count of <20×10/L have the worst prognosis.

Value of multiparameter flow cytometry in the diagnosis and prognostic evaluation of childhood myelodysplastic syndrome / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the value of multiparameter flow cytometry (MFC) and flow cytometric scoring system (FCSS) in the diagnosis and prognostic evaluation of childhood myelodysplastic syndrome (MDS).</p><p><b>METHODS</b>A retrospective analysis was performed for the clinical data of 42 children who were diagnosed with MDS. MFC was performed to investigate the phenotype and proportion of each lineage of bone marrow cells. The correlations of FCSS score with MDS type, International Prognostic Scoring System (IPSS) score, and revised IPSS (IPSS-R) score were analyzed.</p><p><b>RESULTS</b>Of all the 42 children, 20 (48%) had an increase in abnormal marrow blasts, 19 (45%) had a lymphoid/myeloid ratio of >1, 14 (33%) had abnormal cross-lineage expression of lymphoid antigens in myeloid cells, 8 (19%) had abnormal CD13/CD16 differentiation antigens, 5 (12%) had abnormal expression of CD56, 3 (7%) had reduced or increased side scatter of granulocytes, 3 (7%) had reduced expression of CD36 in nucleated red blood cells, 2 (5%) had reduced expression of CD71 in nucleated red blood cells, 1 (2%) had absent expression of CD33 in myeloid cells, 1 (2%) had reduced or absent expression of CD11b in granulocytes, and 1 (2%) had absent expression of CD56 and CD14 in monocytes. There were significant differences in the median overall survival time and event-free survival time among the low-, medium-, and high-risk FCSS groups (P<0.05). Among the low-, medium-, and high-risk FCSS groups, the low-risk FCSS group had the highest 2-year overall survival rate, while there was no significant difference between the medium- and high-risk FCSS groups (P>0.05). The three groups had a 2-year event-free survival rate of 95%, 60%, and 46% respectively (P<0.05). FCSS score was positively correlated with MDS type, IPSS score, and IPSS-R score (P<0.05).</p><p><b>CONCLUSIONS</b>MFC and FCSS help with the diagnosis and prognostic evaluation of childhood MDS.</p>

Clinical characteristics of clonal evolution after immunosuppressive therapy in children with severe/very severe aplastic anemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To evaluate the clinical characteristics and risk factors of clonal evolution after immunosuppressive therapy (IST) in children with severe/very severe aplastic anemia (SAA/VSAA).</p><p><b>METHODS</b>The clinical data of 231 children with newly-diagnosed SAA/VSAA who received IST were retrospectively studied. The incidence and risk factors of clonal evolution after IST were analyzed.</p><p><b>RESULTS</b>The 5-year overall survival rate of the 231 patients was 82.7%. Except for 18 cases of early deaths, 213 patients were evaluated for IST efficacy. Among the 231 patients, cytogenetic abnormalities for at least two chromosome metaphase were detectable in 14 (7.4%) patients, and PNH clones were detectable in either peripheral red blood cells or neutrophils for 95 patients. Among the 213 patients evaluated for IST efficacy, 15 patients experienced clonal evolution after IST. Five patients had PNH and trisomy 8 which were defined as favorable progressions, and ten patients experienced monosomy 7 and MDS/AML as unfavorable progressions. The 5-year accumulative incidence of favorable and unfavorable progression were (2.2±2.2)% and (4.8±3.3)%, respectively. Until the last follow-up, 100% (5/5) of patients with favorable progressions and 50% (5/10) of patients with unfavorable progressions survived. WBC>3.5×10/L, CD3T cell percentage>80%, dosage of antithymocyte globulin >3.0 mg/(kg·d) and no response to IST were related to unfavorable progressions by univariate analysis. Cox multivariate analysis revealed that an increased CD3T cell percentage (>80%) and no response to IST were independent risk factors for unfavorable progressions.</p><p><b>CONCLUSIONS</b>The children with SAA/VSAA who have an increased CD3T cell percentage at diagnosis or have no response to IST are in high risks of unfavorable progressions.</p>

Significance of PAX5 deletion in childhood B-lineage acute lymphoblastic leukemia without reproducible chromosomal abnormalities / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To identify the incidence of PAX5 deletion in childhood B-lineage acute lymphoblastic leukemia (B-ALL) without reproducible chromosomal abnormalities and to investigate the association between PAX5 abnormalities and prognosis of ALL.</p><p><b>METHODS</b>Multiplex ligation-dependent probe amplification was used to determine the copy numbers of PAX5 gene in children newly diagnosed with B-ALL without reproducible chromosomal abnormalities between April 2008 and April 2013 and controls (children with non-hematologic diseases or tumors). The patients were classifiied into deletion group and non-deletion group based on the presence of PAX5 deletion.</p><p><b>RESULTS</b>Eighteen (21%) out of 86 children with B-ALL had PAX5 deletion. The deletion group had a significantly higher total white blood cell count at diagnosis than the non-deletion group (P=0.001). The Kaplan-Meier analysis demonstrated that the deletion group had a significantly lower disease-free survival (DFS) rate than the non-deletion group (0.69±0.12 vs 0.90±0.04; P=0.017), but there was no significant difference in the overall survival rate between the two groups (P=0.128). The Cox analysis showed that PAX5 deletion was a risk factor for DFS (P=0.03).</p><p><b>CONCLUSIONS</b>PAX5 deletion is an independent risk factor for DFS in B-ALL children without reproducible chromosomal abnormalities.</p>

Association between clinical outcome and gene mutation in children with Fanconi anemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the association between clinical outcome and gene mutations in children with Fanconi anemia (FA).</p><p><b>METHODS</b>A retrospective analysis was performed for the clinical data of six children with the same severity of FA and receiving the same treatment. At first, single cell gel electrophoresis and chromosome breakage induced by mitomycin C were performed for diagnosis. Then the gene detection kit for congenital bone marrow failure diseases or complementation test was used for genotyping of FA. Finally the association between the clinical outcome at 3, 6, 9, or 12 months after treatment and gene mutation was analyzed.</p><p><b>RESULTS</b>Of all the six FA children, five had FANCA type disease, and one had FANCM type disease; four children carried two or more FA gene mutations. Among the children with the same severity of FA, those with more FA mutations had a younger age of onset and poorer response to medication, and tended to progress to a severe type.</p><p><b>CONCLUSIONS</b>Children carrying more than two FA mutations have a poor clinical outcome, and hematopoietic stem cell transplantation should be performed as soon as possible.</p>

Detection of copy number variations in pediatric ETV6/RUNX1-positive acute lymphoblastic leukemia with multiplex ligation-dependent probe amplification / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the application of multiplex ligation-dependent probe amplification (MLPA) in the detection of copy number variations (CNVs) in pediatric ETV6/RUNX1-positive acute lymphoblastic leukemia (ALL), to compare this method with conventional karyotype analysis and fluorescence in situ hybridization (FISH), and to evaluate the value of MLPA.</p><p><b>METHODS</b>The clinical data of 95 children with ETV6/RUNX1-positive ALL who were treated from January 2006 to November 2012 were analyzed retrospectively, including clinical features, results of karyotype analysis, and results of FISH. CNVs were detected with MLPA.</p><p><b>RESULTS</b>CNVs were detected in 73 (77%), and the median number of CNVs was 1 (range 0-6). The CNVs of EBF1, CDKN2A/2B, PAX5, ETV6, RB1, and BTG1 were detected in more than 10% of all the patients. The changes in the chromosome segments carrying the genes with CNVs detected by MLPA were not detected by conventional karyotype analysis. The coincidence rate between the CNVs in ETV6 gene detected by FISH and those detected by MLPA was 66%.</p><p><b>CONCLUSIONS</b>MLPA is an efficient and convenient method to detect CNVs in children with ETV6/RUNX1-positive ALL.</p>

Genotype analysis and telomere length measure in patients with dyskeratosis congenita / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To analysze genotype and measure telomere length in two Chinese patients with dyskeratosis congenita(DC).</p><p><b>METHODS</b>The peripleral blood DNA was extracted in two patients characterized by mucocutaneous abnormalities (abnormal nails, lacy reticulated skin pigmentation, and oral leukoplakia), bone marrow failure, DC genes were amplified by polymerase chain reaction (PCR), including DKC1, TERT, TERC, TINF2, NOP10, NHP2, then DNA sequencing was performed for abnormal exons. Lymphocyte telomere length was measured by flow cytometry-fluorescence in situ hybridization(Flow-FISH).</p><p><b>RESULTS</b>Abnormal peaks were found in exon 6 of TINF2 gene of the two patients and a 811C→T transition in TINF2 gene in one patient. DNA sequencing showed a 848C→A transition in TINF2 gene in another patient. Relative telomere length was remarkable less than that of normal children with same age.</p><p><b>CONCLUSIONS</b>Physician should think about DC if the young patients with mucocutaneous abnormalities and marrow failure. Early detection of related genes and measurernant of tolomere length may contribute to avoid misdiagnosis. TINF2 c.811C→T (Q271X) and TINF2 c.848C→A (P283H) exist in the two patients, it is reported in China for the first time.</p>

Copy number variations in pediatric acute myeloid leukemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To evaluate the copy number variations (CNV) of gene in pediatric acute myeloid leukemia (AML) and its correlation with clinical features and prognosis.</p><p><b>METHODS</b>The clinical data of 130 children aged <14 years with newly diagnosed AML from May 2006 to March 2013 were analyzed restrospectively. The CNV were analyzed by multiplex ligation-dependent probe amplification (MLPA). Thirty-eight normal children were selected in control group. All the data were statistically analyzed using SPSS16.0 software.</p><p><b>RESULTS</b>gene CNV of 2p24.3(MYCN), 10q23(PTEN) and 13q14(RB1, MIR15A, DLEU) were detected in more than 10% of the patients. CNV were detected in 49 cases(37.7%). The median loss and gain CNV frequencies per sample were 4. The CNV of TP53 correlated significantly with relapse. The loss ond gain CNV have no influence to EFS, DSF and OS. CNV were detected in the twelve percent of patients, but they were not detected with routine karyotype method.</p><p><b>CONCLUSION</b>The MLPA technique combined with karyotyping makes a substantial increase in the diagnostic rate. Patients with TP53 alterations have significantly higher relapse rate.</p>

Clinical features of children with relapsed acute lymphoblastic leukemia treated with the CCLG-ALL2008 protocol / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical features of children with relapsed acute lymphoblastic leukemia (ALL) treated with the CCLG-ALL2008 protocol.</p><p><b>METHODS</b>The data of 591 children who were newly diagnosed with ALL and were treated with the CCLG-ALL 2008 protocol between April 2008 and June 2013 were collected, and the clinical features of 80 children with relapsed ALL were retrospectively analyzed.</p><p><b>RESULTS</b>After treatment with the CCLG-ALL2008 protocol, the recurrence rate in the standard-risk, intermediate-risk and the high-risk groups were 7.0%, 10.7% and 28.7% respectively (P<0.05). The recurrence rate in patients with TEL/AML1-positive ALL was 8.0%, and the 5-year overall survival (OS) of the relapsed patients was 37.04%. The recurrence rates in patients with MLL-positive and BCR/ABL-positive ALL were 35.0% and 24.2% respectively, and none of the relapsed patients had long-term survival. The recurrence mainly occurred at the very early stage (53%), and none of patients with recurrence at the very early stage had long-term survival. The recurrence occurred at early stage and late stage accounted for 34% and 14% respectively, and the 5-year OS rates of patients with recurrence at early stage and late stage were 11.44% and 60.00% respectively. The sites of recurrence were mainly bone marrow alone (83%), and the 5-year OS of patients with recurrence at bone marrow alone was 9.23%. The recurrence in bone marrow and outside bone marrow accounted for 11%, and the 5-year OS of patients with recurrence in both bone marrow and outside bone marrow was 25.00%. The recurrence only outside bone marrow accounted for 6%, and the 5-year OS of patients with recurrence only outside bone marrow was 100%. The recurrence rate in patients with T-cell ALL was 9.5%, and none of the relapsed patients had long-term survival. The recurrence rate in patients with B-cell ALL was 14.3%, and the 5-year OS of the relapsed patients was 15.52%.</p><p><b>CONCLUSIONS</b>After treatment with the CCLG-ALL2008 protocol, a relatively high recurrence rate is observed in children with high-risk ALL. Positive MLL and positive BCR/ABL are high-risk factors for recurrence. The recurrence rate is not significantly correlated with immunophenotype. A very low survival rate is seen in children whose recurrence have the following features: at early stage, only in bone marrow, T-cell ALL, and abnormal BCR/ABL and MLL.</p>

Prognostic Value of Prednisone Response in CCLG-ALL 2008 / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To ovaluate the prognostic value of prednisone response in treatment regimes of children with acute lymphoblastic leukemia.</p><p><b>METHODS</b>A total of 598 newly diagnosed ALL patients were enrolled and received prednisone pre-treatment. Based on the peripheral lymphoblast count on day 8, these patients were divided into 2 groups: prednisone good response (PGR) and prednisone poor response (PPR). PPR patients were classified into high risk group immediately and then received intensed chemotherapy. The all enrolled patients were followed up and the clinical features and treatment outcomes of the two groups were analyzed.</p><p><b>RESULTS</b>Compared with PGR group, PPR group had different characteristics. They were older in age and had higher initial white blood cell count (P<0.05). T-cell ALL (T-ALL) and Philadelphia chromosome positive ALL (Ph+ ALL) were frequent in PPR group (P<0.05). Event-free survival (EFS) rate of PPR group was significantly lower than that of PGR group (P<0.05). 2 year event-free survival(EFS) rate of PGR group was (88.3±1.5)%, while the 2-year EFS rate of PPR group was (58.4±5.3)%. 5 year EFS rates of PGR and PPR were (80.8±2.1)% and (53.4±6.0)%, respectively. The EFS rate of PPR group was falling rapidly within 2 years. PPR group had higher relapse rate, and most relapses occurred within 18 months (P<0.05). PPR group had more high incidence of minimal residual disease (MRD) both on day 33 and on week 12 (P<0.05). No significant difference of EFS and relapse time was found between PPR and high risk PGR patients (P>0.05). In multi-variate regression analysis, the PPR, the presence of BCR-ABL1 and MLL were significantly unfavorable factors (P<0.05).</p><p><b>CONCLUSION</b>Prednisone response has been confirmed to be still great prognostic value and PPR children patients have poor outcomes generally. It is likely that the response to prednisone does not make much sense to high risk ALL patients.</p>

Gene mutations and clinical characteristics in children with juvenile myelomonocytic leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study gene mutations and clinical features in children with juvenile myelomonocytic leukemia (JMML).</p><p><b>METHODS</b>The clinical data of 14 children who were diagnosed with JMML and were examined for the detection of common gene mutations were retrospectively analyzed.</p><p><b>RESULTS</b>Eleven (79%) out of 14 cases were male, and 3 (21%) were female. The median age at diagnosis was 2.0 years (age range: 0.6-6.0 years). Among 14 cases, there were 4 cases (29%) with PTPN11 mutation, 3 cases (21%) with N-RAS mutation, 1 case (7%) with PTPN11 mutation and K-RAS mutation, and 6 cases (43%) without any mutation. All four cases in the PTPN11 mutation group were male, and their median age was 2.5 years; interval from onset to diagnosis was 1.0 month; the white blood cell (WBC) count and absolute monocytes in peripheral blood were significantly higher, while the platelet (PLT) count was lower, as compared with the other three groups; they were followed up, and 3 cases died and 1 case had a progressive disease. In the N-RAS mutation group, there were two male cases and one female case, and their median age was 2.0 years; interval from onset to diagnosis was 13.7 months; after follow-up, 2 cases died and 1 case did not have an obviously progressive disease.</p><p><b>CONCLUSIONS</b>PTPN11 mutation is the most common mutation in JMML. The cases with PTPN11 mutation often have higher WBC count and absolute monocytes in peripheral blood, a lower PLT count, and a rapid disease progression, and their clinical outcomes are poor. The cases with N-RAS mutation have a slow disease progression. The clinical characteristics of the patients with compound mutations are not sure because of the small number of cases, and further clinical observation is indispensable.</p>

Methylation of the genes in the 9P21 region in children with acute myeloid leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the methylation rate of cyclin-dependent kinase inhibitor 2A (CDKN2A) and cyclin-dependent kinase inhibitor 2B (CDKN2B) in the 9P21 region in children with acute myeloid leukemia (AML) and the association of gene methylation with clinical features and outcomes.</p><p><b>METHODS</b>The clinical data of 58 children who were newly diagnosed with AML between January 2010 and December 2012 were retrospectively analyzed. Thirty-eight healthy children were recruited as the control group. Genomic DNA was extracted from bone marrow or peripheral blood of the 58 patients and 38 healthy children. The methylation status of CDKN2A and CDKN2B was analyzed by methylation-specific multiplex ligation-dependent probe amplification.</p><p><b>RESULTS</b>Gene methylation was not found in healthy children. Methylation probes of 44 patients were detected in 58 patients. The methylation of CDKN2A was detected with 136 bp and 237 bp methylation probes. The methylation of CDKN2B was detected with 130 bp, 210 bp, 220 bp, and 417 bp methylation probes. The methylation rate of CDKN2A was 5%, while the methylation rate of CDKN2B was 76%. The methylation detected by some probes was associated with sex, hemoglobin, and platelet count at the first visit.</p><p><b>CONCLUSIONS</b>The methylation of CDKN2B is a common event in children with AML, while the methylation of CDKN2A is relatively rare.</p>

Significance of IKZF1 gene copy number abnormalities in BCR/ABL-negative B-lineage acute lymphoblastic leukemia in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To identify IKZF1 gene copy number abnormalities in BCR/ABL-negative B-lineage acute lymphoblastic leukemia (B-ALL) in children, and to investigate the association between such abnormalities and prognosis.</p><p><b>METHODS</b>Multiplex ligation-dependent probe amplification (MLPA) was applied to detect IKZF1 gene copy number abnormalities in 180 children diagnosed with BCR/ABL-negative B-ALL. These children were classified into IKZF1 deletion group and IKZF1 normal group according to the presence or absence of IKZF1 gene deletion. The association between IKZF1 copy number abnormalities and prognosis of children with BCR/ABL-negative B-ALL was analyzed retrospectively.</p><p><b>RESULTS</b>Among 180 children, 27 (15.0%) had IKZF1 deletion; among the 27 children, 4 had complete deletions of 8 exons of IKZF1 gene, 17 had deletion of exon 1, 3 had deletions of exons 4-7, and 3 children had deletions of exons 2-7. Compared with those in the IKZF1 normal group, children in the IKZF1 deletion group had higher white blood cell (WBC) count and percentage of individuals with high risk of minimal residual disease at the first visit. IKZF1 deletions often occurred in BCR/ABL-negative children with no special fusion gene abnormalities. They were frequently accompanied by abnormalities in chromosomes 11, 8, 5, 7, and 21. The analysis with Kaplan-Meier method showed that disease-free survival (DFS) in the IKZF1 deletion group was significantly lower than that in the IKZF1 normal group (0.740 ± 0.096 vs 0.905 ± 0.034; P=0.002). Cox analysis showed that after exclusion of sex, age, initial WBC count, cerebrospinal fluid state at the first visit, prednisone response, and chromosome karyotype, IKZF1 deletion still affected the children's DFS (P<0.05).</p><p><b>CONCLUSIONS</b>Some children with BCR/ABL-negative B-ALL have IKZF1 deletion, and IKZF1 deletion is an independent risk factor for DFS in children with BCR/ABL-negative B-ALL.</p>

Efficacy and safety of imatinib for the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the efficacy and safety of Chinese Childhood Leukemia Group ALL 2008 (CCLG-ALL2008) protocol combined with tyrosine kinase inhibitor (TKI, imatinib) for the treatment of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) in children.</p><p><b>METHODS</b>The clinical data of 53 patients aged less than 15 years when first diagnosed with Ph+ ALL between October 2008 and December 2013 were retrospectively analyzed. The patients were assigned to two groups: HR (n=26) and HR+TKI (n=27). The HR group was treated with CCLG-ALL2008 protocol (for high-risk patients). The HR+TKI group was treated with imatinib in combination with CCLG-ALL2008 protocol (for high-risk patients).</p><p><b>RESULTS</b>The complete remission rate and chemotherapy induction-related mortality rate in the TKI+HR and HR groups were 100% vs 75% and 0 vs 15%, respectively. The 3-year event-free survival (EFS) rate in the HR group was (6±5)%; the 5-year EFS rate of the TKI+HR group was (52±11)%. Compared with the HR group, the TKI+HR group had no increase in the toxic responses to chemotherapy and had a decrease in the infection rate during the induction period.</p><p><b>CONCLUSIONS</b>Application of imatinib significantly improves the clinical efficacy in children with Ph+ ALL and has good safety.</p>

Long-term efficacy of CAMSBDH-ALL chemotherapy protocol for the treatment of childhood acute lymphoblastic leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the long-term efficacy of CAMSBDH-ALL chemotherapy protocol for the treatment of childhood acute lymphoblastic leukemia (ALL).</p><p><b>METHODS</b>Three hundred and eighteen children who were newly diagnosed with ALL between January 1999 and December 2007 were enrolled in this study. Among the 318 children, 83 children who hospitalized before December 2002 were treated with CAMSBDH-ALL99 protocol, including 48 patients of standard risk and 35 patients of high risk. The patients (n=235; 131 in standard risk and 104 in high risk) who hospitalized after December 2002 were treated with CAMSBDH-ALL03 protocol. Patients in the CAMSBDH-ALL99 protocol group were treated with conventional chemotherapy. CAMSBDH-ALL03 protocol was modified based on the CAMSBDH-ALL99 protocol.</p><p><b>RESULTS</b>The long-term overall survival (OS) and event-free-survival (EFS) in the CAMSBDH-ALL03 group was significantly higher than in the CAMSBDH-ALL99 (P<0.01). The long-term OS and EFS of standard risk and high risk patients in the CAMSBDH-ALL03 protocol group were significantly higher than in the CAMSBDH-ALL99 protocol group (P<0.01). The CAMSBDH-ALL03 protocol group showed a significantly lower recurrence rate (28.9%) than in the CAMSBDH-ALL99 protocol group (50.6%) (P<0.05). The mortality rate in the CAMSBDH-ALL03 protocol group was 28.5% vs 56.6% in the CAMSBDH-ALL99 protocol group (P<0.05).</p><p><b>CONCLUSIONS</b>The therapeutic effect of the CAMSBDH-ALL03 protocol is supior to the CAMSBDH-ALL99 protocol group for childhood ALL, with a higher long-term survival rate.</p>

Correlation of single-cell gel electrophoresis and mitomycin C-induced chromosomal breakage for chromosomal instabiligy in children with Fanconi anemia / 中华儿科杂志

<p><b>OBJECTIVE</b>Fanconi anemia (FA) is characterized by bone marrow failure, congenital abnormalities and predisposition to neoplasia. Hypersensitivity of FA cells to the clastogenic effect of mitomycin C (MMC) provides a unique marker for the diagnosis before the beginning of hematological manifestations. The aim of this study was to evaluate the relationship between Single-Cell Gel Electrophoresis (SCGE) and mitomycin C-induced chromosomal breakage in children with FA.</p><p><b>METHOD</b>Between January 2007 and June 2011, 248 children (< 15 years) with hypocytosis were included. Chromosomal breakage was induced by MMC 0 ng/ml, 40 ng/ml, and 80 ng/ml. SCGE was performed at the same time. We analyzed the results of the two methods and compared with each other. The receiver operating characteristic (ROC) curve was used to evaluate the parameters in SCGE.</p><p><b>RESULT</b>Seventeen patients were diagnosed as FA and 231 as non-FA. Chromosomal breakage was found to be significantly higher in FA patients [(32.2 ± 4.8)%] than non-FA [(19.9 ± 3.0)%] and controls[(21.6 ± 4.8)%] when induced by MMC 80 ng/ml. The parameters of SCGE were significantly different between FA patients and non-FA or controls. All the parameters were rectilinearly correlated with MMC (P = 0.000). The most closely correlated parameter was the rate of comet cell (r = 0.848, P = 0.000). The results of ROC curves suggested the comet cell rate (0.999) was more important.</p><p><b>CONCLUSION</b>SCGE might be used to discriminate between FA and non-FA individuals. The relationship between SCGE and MMC-induced chromosomal breakage was significant. The rate of comet cell was the important parameter.</p>