Long-term outcomes of 172 children with severe aplastic anemia treated with rabbit antithymocyte globulin and cyclosporine.

This study retrospectively analyzed the clinical outcome of 172 children with newly diagnosed severe aplastic anemia (SAA) between January 2008 and April 2018, who received rabbit antithymocyte globulin (ATG) and cyclosporine (CsA) as first-line treatment. The median age at diagnosis was 5 years (range, 1-14). The overall response rates were 22.7%, 45.3%, and 61% at 40 days, 3 months, and 6 months, respectively, after rabbit ATG. In multivariate analysis, mild disease severity was the only predictor of favorable response at 6 months (P = 0.006). In the present study, median follow-up period was 63 months (range, 1-135). The 5-year overall survival (OS) and failure-free survival (FFS) rates were 90.5% and 70.4%. Multivariate analysis showed that erythroid burst-forming units (BFU-E) > 2/105 bone marrow mononuclear cell (BMMNC) (P = 0.037) and time interval before IST ≤ 30 days (P = 0.017) were independent positive predictors for OS, meanwhile BFU-E > 2/105BMMNC (P = 0.029) was the only favorable prognostic factor for FFS.

[CD20 is not a poor prognostic factor for childhood B-lineage acute lymphoblastic leukemia with high white blood cell count].

OBJECTIVE: To study the significance of CD20 combined with white blood cell (WBC) count at diagnosis in the prognosis assessment in children with B-lineage acute lymphoblastic leukemia (ALL). METHODS: A retrospective analysis was performed on the medical data of 821 B-ALL children who were treated with CCLG-ALL2008 regimen from April 2008 to April 2015. Their survival status was followed up. RESULTS: Among the 821 children, 547 (66.6%) were negative, while 274 (33.4%) were positive for CD20 expression. Among 694 children with WBC<50×109/L (lower WBC count), the 5-year EFS rates were 65.9%±3.2% and 77.3%±2.0% for CD20 positive and negative patients respectively (P=0.001); the 5-year OS rates were 78.3%±2.9% and 87.5%±1.6% for CD20 positive and negative patients respectively (P=0.005); CD20 positive expression was an independent risk factor for EFS (HR=1.634, P=0.001) and OS (HR=1.761, P=0.005). Among 127 children with WBC>50×109/L (higher WBC count), the 5-year EFS rates was 64.3%±7.7% and 53.7%±5.5% for CD20 positive and negative patients respectively (P=0.135); the 5-year OS rate was 81.4%±6.4% and 58.6%±5.6% for CD20 positive and negative patients respectively (P=0.022); CD20 positive expression was an independent protective factor for OS (HR=0.367, P=0.016). CONCLUSIONS: In children with B-ALL who are treated with CCLG-ALL2008 regimen, those with CD20 positive expression in lower WBC count at diagnosis have a poor prognosis; however, those with CD20 positive expression in higher WBC count at diagnosis have a better long-time survival.

[Association of cerebrospinal fluid status with prognosis in children with acute lymphoblastic leukemia].

OBJECTIVE: To study the clinical features of central nervous system infiltration-positive (CNSI+) children with acute lymphoblastic leukemia (ALL) based on flow cytometry, as well as the association of such clinical features with prognosis. METHODS: A retrospective analysis was performed for the clinical data of 66 CNSI+ children with ALL treated from April 2008 to June 2013. Clinical features, laboratory examination results and prognosis were compared between the children in different chemotherapy stages (induction stage and consolidation/maintenance stage). RESULTS: Among the 66 CNSI+ children, 50 were in the induction stage and 16 in the consolidation/maintenance stage. Compared with the CNSI+ children in the induction stage, the CNSI+ children in the consolidation/maintenance stage had a significantly higher proportion of children with the genes associated with good prognosis based on the results of molecular biology (P<0.05), as well as a significantly higher recurrence rate (P<0.05). Recurrence was observed in 21 CNSI+ ALL children, among whom 10 were in the induction stage and 11 were in the consolidation/maintenance stage. Compared with the children experiencing recurrence in the induction stage, the children experiencing recurrence in the consolidation/maintenance stage had a significantly higher proportion of children with recurrence of the central nervous system and bone marrow (P<0.05), as well as significantly higher proportion of biochemical positive rate of cerebrospinal fluid (P<0.05). The children in the induction stage had a significantly higher recurrence-free survival rate than those in the consolidation/maintenance stage (P<0.001), while there was no significant difference in overall survival rate between the two groups (P>0.05). CONCLUSIONS: In children with ALL, CNSI+ has a marked effect on recurrence-free survival rate in different chemotherapy stages, but has no obvious effect on overall survival rate. CNSI+ patients in the consolidation/maintenance stage have a higher recurrence.

A Robust Method for Automatic Panoramic UAV Image Mosaic.

This paper introduces a robust method for panoramic unmanned aerial vehicle (UAV) image mosaic. In the traditional automatic panoramic image stitching method (Autostitch), it assumes that the camera rotates about its optical centre and the group of transformations the source images may undergo is a special group of homographies. It is rare to get such ideal data in reality. In particular, remote sensing images obtained by UAV do not satisfy such an ideal situation, where the images may not be on a plane yet and even may suffer from nonrigid changes, leading to poor mosaic results. To overcome the above mentioned challenges, in this paper a nonrigid matching algorithm is introduced to the mosaic system to generate accurate feature matching on remote sensing images. We also propose a new strategy for bundle adjustment to make the mosaic system suitable for the UAV image panoramic mosaic effect. Experimental results show that our method outperforms the traditional method and some of the latest methods in terms of visual effect.

[Clinical features and gene mutation spectrum in children with sideroblastic anemia].

OBJECTIVE: To study the clinical features and gene mutation spectrum of children with sideroblastic anemia (SA) and the clinical value of targeted next-generation sequencing in the molecular diagnosis of children with SA. METHODS: Clinical data were collected from 36 children with SA. Targeted next-generation sequencing was used to detect mutations in SA-related pathogenic genes and genes associated with heme synthesis and mitochondrial iron metabolism. The association between genotype and clinical phenotype was analyzed. RESULTS: Of the 36 patients, 32 had congenital sideroblastic anemia (CSA) and 4 had myelodysplastic syndrome with ring sideroblasts (MDS-RS). Mutations in CSA-related genes were detected in 19 children (19/36, 53%), among whom 9 (47%) had ALAS2 mutation, 4 (21%) had SLC25A38 mutation, and 6 (32%) had mitochondrial fragment deletion. No pathogenic gene mutation was detected in 4 children with MDS-RS. Among the 19 mutations, 89% (17/19) were known mutations and 11% (2/19) were novel mutations. The novel mutation of the ALAS2 gene c.1153A>T(p.I385F) was rated as "possibly pathogenic" and the novel mutation of the SLC25A38 gene c.175C>T(p.Q59X) was rated as "pathogenic". CONCLUSIONS: ALAS2 and SLC25A38 gene mutations are commonly seen in children with CSA, but mitochondrial gene fragment deletion also accounts for a relatively high proportion. For children with hypoplastic anemia occurring in infancy, mitochondrial disease should be considered.

[Long-term clinical effect of the CCLG-ALL2008 regimen in treatment of childhood acute lymphoblastic leukemia with different molecular biological features].

OBJECTIVE: To study the long-term clinical effect of the CCLG-ALL2008 regimen in the treatment of children newly diagnosed with acute lymphoblastic leukemia (ALL) with different molecular biological features. METHODS: A total of 940 children who were newly diagnosed with ALL were enrolled in this study. The children were treated with the CCLG-ALL2008 regimen. A retrospective analysis was performed for the long-term outcome of ALL children with different molecular biological features. RESULTS: Among the 940 children with ALL, there were 570 boys and 370 girls, with a median age of onset of 5 years (range 1-15 years) and a median follow-up time of 65 months (range 3-123 months). The complete response (CR) rate was 96.7%, the predicted 10-year overall survival (OS) rate was 76.5%±1.5%, and the event-free survival (EFS) rate was 62.6%±3.0%. After CR was achieved after treatment, the overall recurrence rate was 21.9%. The children with positive ETV6-RUNX1 had the lowest recurrence rate and were prone to late recurrence, and those with positive MLL rearrangement had the highest recurrence rate and were prone to early recurrence. The children with positive ETV6-RUNX1 had a significantly higher predicted 10-year OS rate than those with positive TCF3-PBX1, BCR-ABL, or MLL rearrangement and those without molecular biological features (P<0.05). The children with positive ETV6-RUNX1 had a significantly higher predicted 10-year EFS rate than those with positive BCR-ABL or MLL rearrangement (P<0.05). CONCLUSIONS: Molecular biological features may affect the long-term prognosis of children with ALL, and positive MLL rearrangement and BCR-ABL fusion gene are indicators of poor prognosis. Children with positive ETV6-RUNX1 fusion gene have the highest long-term survival rate.

[Mitoxantrone-cytarabine-etoposide induction therapy in children with acute myeloid leukemia: a single-center study of complications and clinical outcomes].

OBJECTIVE: To investigate the complications and clinical outcome of children with acute myeloid leukemia (AML) undergoing mitoxantrone-cytarabine-etoposide (MAE) induction therapy. METHODS: A total of 170 children with AML were given MAE induction therapy, and the complications and remission rate were analyzed after treatment. RESULTS: The male/female ratio was 1.33:1 and the mean age was 7.4 years (range 1-15 years). Leukocyte count at diagnosis was 29.52×109/L [range (0.77-351)×109/L]. Of all children, 2 had M0-AML, 24 had M2-AML, 2 had M4-AML, 48 had M5-AML, 3 had M6-AML, 7 had M7-AML, 69 had AML with t(8;21)(q22;q22), and 15 had AML with inv(16)(p13.1q22) or t(16;16)(p13.1;q22). The most common complication was infection (158/170, 92.9%). Among these 158 patients, 22 (13.9%) had agranulocytosis with pyrexia (with no definite focus of infection), and 136 (86.1%) had definite focus of infection (including bloodstream infection). Other complications included non-infectious diarrhea, bleeding, and drug-induced hepatitis. Treatment-related mortality was observed in 10 children, among whom 8 had severe infection, 1 had multiple organ failure, and 1 had respiratory failure. Remission rate was evaluated for 156 children and the results showed a complete remission rate of 85.3%, a partial remission rate of 4.5%, and a non-remission rate of 10.3%. CONCLUSIONS: Induction therapy with the MAE regimen helps to achieve a good remission rate in children with AML after one course of treatment. Infection is the main complication and a major cause of treatment-related mortality.

[Clinical features and prognosis of children with acute lymphoblastic leukemia and different platelet levels].

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 <100×109/L; n=629). The thrombocytopenia group was further divided into (50- <100)×109/L (n=243), (20- <50)×109/L (n=263), and <20×109/L (n=123) subgroups. The association of clinical features (sex, age, immunophenotype, and molecular biology) with event-free survival (EFS) and overall survival (OS) was analyzed. RESULTS: Compared with the thrombocytopenia group, the normal platelet count group had significantly lower positive rate of MLL gene rearrangement and recurrence rate (P<0.05), as well as a significantly higher 10-year EFS rate (P<0.05). There was no significant difference in 10-year OS between the two groups (P>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 (P<0.05), and there was still no significant difference in 10-year OS between the two groups (P>0.05). The <20×109/L subgroup had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50- <100)×109/L subgroup, and the (20- <50)×109/L subgroup (P<0.05). After the children with MLL gene rearrangement were excluded, the <20×109/L subgroup still had significantly lower 10-year EFS and OS rates than the normal platelet count group, the (50-<100)×109/L subgroup, and the (20- <50)×109/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 <20×109/L have the worst prognosis.

Heat-shock transcription factor 1 is critically involved in the ischaemia-induced cardiac hypertrophy via JAK2/STAT3 pathway.

Cardiac hypertrophy after myocardial infarction (MI) is an independent risk factor for heart failure. Regression of cardiac hypertrophy has emerged as a promising strategy in the treatment of MI patients. Here, we have been suggested that heat-shock transcription factor 1 (HSF1) is a novel repressor of ischaemia-induced cardiac hypertrophy. Ligation of left anterior descending coronary was used to produce MI in HSF1-deficient heterozygote (KO), HSF1 transgenic (TG) mice and their wild-type (WT) littermates, respectively. Neonatal rat cardiomyocytes (NRCMs) were treated by hypoxia to mimic MI in vitro. The HSF1 phosphorylation was significantly reduced in the infarct border zone of mouse left ventricles (LVs) 1 week after MI and in the hypoxia-treated NRCMs. HSF1 KO mice showed more significant maladaptive cardiac hypertrophy and deteriorated cardiac dysfunction 1 week after MI compared to WT MI mice. Deficiency of HSF1 by siRNA transfection notably increased the hypoxia-induced myocardial hypertrophy in NRCMs. Mechanistically, Janus kinase 2 (JAK2) and its effector, signal transducer and activator of transcription 3 (STAT3) were found to be significantly increased in the LV infarct border zone of WT mice after MI as well as the NRCMs treated by hypoxia. These alterations were more significant in HSF1 KO mice and NRCMs transfected with HSF1 SiRNA. Inversely, HSF1 TG mice showed significantly ameliorated cardiac hypertrophy and heart failure 1 week after LAD ligation compared to their WT littermates. Our data collectively demonstrated that HSF1 is critically involved in the pathological cardiac hypertrophy after MI via modulating JAK2/STAT3 signalling and may constitute a potential therapeutic target for MI patients.

Role of cytarabine in paediatric acute promyelocytic leukemia treated with the combination of all-trans retinoic acid and arsenic trioxide: a randomized controlled trial.

BACKGROUND: The combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) has been suggested to be safe and effective for adult acute promyelocytic leukaemia (APL). As of 2010, the role of cytarabine (Ara-C) in APL was controversial. The aim of this study was to test the efficacy and safety of ATRA and ATO in paediatric APL patients. Also, we assessed whether Ara-C could be omitted in ATO and ATRA- based trials in children. METHODS: We performed a randomized controlled trial in paediatric APL patients (≤14 years of age) in our hospital from May 2010 to December 2016. All of the patients were assigned to receive ATRA plus ATO for induction followed by one course of idarubicin (IDA) and ATO (28 days). The patients were then randomly assigned to receive two courses of daunorubicin (DNR, no- Ara-C group) or DNR + Ara-C (Ara-C group). All of the patients were followed with maintenance therapy with oral ATRA, 6-mercaptopurine, and methotrexate for 1.5 years. RESULTS: Among the 66 patients, 43 were male and 23 were female. All of the patients achieved complete remission (CR) with the exception of one who gave up the treatment. During induction therapy, all toxicity events were reversed after appropriate management. Thirty patients in the Ara-C group underwent 57 courses of treatment, and 35 patients in the no-Ara-C group underwent 73 courses of treatment. No significant differences in age, genders, white blood cell counts, haemoglobin levels, and platelet counts were found between the Ara-C and no-Ara-c groups. Greater myelosuppression and sepsis were observed in the Ara-C group during the consolidation courses. No patient died at consolidation, and only one patient relapsed. No differences were found in event-free survival, disease-free survival and overall survival between the two groups. Additionally, our analysis of the arsenic levels in the plasma, urine, hair and nails of the patients indicated that no significant accumulation of arsenic occurred after ATO was discontinued for 12 months. CONCLUSIONS: Overall, ATO and ATRA are safe and effective for paediatric APL patients and Ara-C could be omitted when ATO is used for two courses. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT01191541 , retrospectively registered on 18 August 2010).

[Clinical characteristics of clonal evolution after immunosuppressive therapy in children with severe/very severe aplastic anemia].

OBJECTIVE: 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). METHODS: 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. RESULTS: 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>3.5×109/L, CD3+T 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 CD3+T cell percentage (>80%) and no response to IST were independent risk factors for unfavorable progressions. CONCLUSIONS: The children with SAA/VSAA who have an increased CD3+T cell percentage at diagnosis or have no response to IST are in high risks of unfavorable progressions.

[Significance of PAX5 deletion in childhood B-lineage acute lymphoblastic leukemia without reproducible chromosomal abnormalities].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: PAX5 deletion is an independent risk factor for DFS in B-ALL children without reproducible chromosomal abnormalities.

[Detection of copy number variations in pediatric ETV6/RUNX1-positive acute lymphoblastic leukemia with multiplex ligation-dependent probe amplification].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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%. CONCLUSIONS: MLPA is an efficient and convenient method to detect CNVs in children with ETV6/RUNX1-positive ALL.

Identification of Chinese plague foci from long-term epidemiological data.

Carrying out statistical analysis over an extensive dataset of human plague reports in Chinese villages from 1772 to 1964, we identified plague endemic territories in China (i.e., plague foci). Analyses rely on (i) a clustering method that groups time series based on their time-frequency resemblances and (ii) an ecological niche model that helps identify plague suitable territories characterized by value ranges for a set of predefined environmental variables. Results from both statistical tools indicate the existence of two disconnected plague territories corresponding to Northern and Southern China. Altogether, at least four well defined independent foci are identified. Their contours compare favorably with field observations. Potential and limitations of inferring plague foci and dynamics using epidemiological data is discussed.

[Gene mutations and clinical characteristics in children with juvenile myelomonocytic leukemia].

OBJECTIVE: To study gene mutations and clinical features in children with juvenile myelomonocytic leukemia (JMML). METHODS: The clinical data of 14 children who were diagnosed with JMML and were examined for the detection of common gene mutations were retrospectively analyzed. RESULTS: 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. CONCLUSIONS: 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.

[Clinical features of childhood refractory cytopenia].

OBJECTIVE: To study the clinical features of patients with refractory cytopenia of childhood (RCC). METHODS: The clinical data of 1 420 children (0-14 years old) with an initial diagnosis of non-severe aplastic anemia between January 1990 and June 2013 were retrospectively analyzed. Bone marrow cell morphology and histopathology were re-evaluated, and the patients were re-classified using the criteria proposed in the 2008 edition of the World Health Organization classification of RCC in hematopoietic and lymphoid tumor tissues. The clinical outcomes were followed up every 3-6 months. RESULTS: Among all the 1 420 cases, 152 (10.7%) were reassessed as RCC. Patients with RCC had a lower level of hemoglobin and a higher percentage of fetal hemoglobin than those with non-severe aplastic anemia. Of the patients with RCC, 21.5% showed abnormal karyotypes at diagnosis. The median follow-up period for all patients was 36 months (ranging from 1 to 283 months). The rates of complete response, partial response, and no response to cyclosporine and androgen treatment in RCC patients were 19.0%, 26.7%, and 54.3%, respectively. The 5- and 10-year prospective overall survival rates of RCC patients were 87.9% and 72.4%, respectively. The 5- and 10-year prospective clonal evolution rates were 15.3% and 20.0%, respectively. The 2-year prospective incidence of newly diagnosed karyotype abnormality after the initial diagnosis was 3.6%. The 5- and 10-year prospective leukemia transformation rates were 10.0% and 20.0%, respectively. CONCLUSIONS: RCC shows clinical features similar to adult myelodysplastic syndrome. Children with RCC have a poor prognosis, an increased risk of transformation to leukemia, and a low response rate to cyclosporine treatment.

[Significance of IKZF1 gene copy number abnormalities in BCR/ABL-negative B-lineage acute lymphoblastic leukemia in children].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

[Efficacy and safety of imatinib for the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia in children].

OBJECTIVE: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: Application of imatinib significantly improves the clinical efficacy in children with Ph+ ALL and has good safety.

[Clinical features of children with relapsed acute lymphoblastic leukemia treated with the CCLG-ALL2008 protocol].

OBJECTIVE: To study the clinical features of children with relapsed acute lymphoblastic leukemia (ALL) treated with the CCLG-ALL2008 protocol. METHODS: 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. RESULTS: 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%. CONCLUSIONS: 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.

[Methylation of the genes in the 9P21 region in children with acute myeloid leukemia].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: The methylation of CDKN2B is a common event in children with AML, while the methylation of CDKN2A is relatively rare.