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Objective:To explore the clinical significance of the MYCN gene, PHOX2B gene and plasma cell-free DNA (cfDNA) in risk stratification and predicting the prognosis of high-risk neuroblastoma (NB). Methods:This was a prospective study involving 94 high-risk NB children admitted to Beijing Children′s Hospital, Capital Medical University from August 2017 to December 2018.Relative levels of MYCN and PHOX2B and cfDNA at diagnosis, and 4 and 6 cycles of chemotherapy were detected, and their differences were compared by the Chi- square test.Kaplan-Meier survival analysis was performed to explore their prognostic potential in high-risk NB. Results:Among the 94 high-risk NB children, 14 cases (14.9%) had MYCN amplification, 76 cases (80.8%) had positive expression of PHOX2B and 56 cases (59.6%) had cfDNA level higher than 100 μg/L.The proportion of high lactate dehydrogenase (LDH, ≥1 500 U/L) level in the MYCN gene amplification group (6/14 cases) was higher than that in the normal group (9/80 cases) ( P=0.009). The proportion of multi-site metastasis (54/76 cases) and high neuron specific enolase (NSE) level (NSE≥370 μg/L, 37/76 cases) in PHOX2B positive group were significantly higher than those in the negative group (5/14 cases, 2/14 cases) ( P=0.015, 0.020). The proportion of high LDH and high NSE in high cfDNA concentration (≥229.6 μg/L)group (13/37 cases, 28/37 cases) were significantly higher than those in low cfDNA concentration group (2/48 cases, 10/48 cases) (all P<0.001). With the decreased tumor burden during the treatment, the copy number of PHOX2B gene and cfDNA level were significantly lower than those at the initial diagnosis [0 (0-719.6) copies vs.1 723.5 (0-186 000.0) copies; 19.0 (1.1-225.5) μg/L vs.200.6 (8.0-5 247.4) μg/L, all P<0.001]. The 2-year event-free survival (EFS) rate of the MYCN gene amplification group was significantly lower than that of the normal group[(33.3±13.1)% vs.(58.5±7.1)%, P=0.020]. The 2-year EFS rate of PHOX2B positive group was significantly lower than that of the negative group[(47.9±7.1)% vs.(79.1±11.1)%, P=0.043]. EFS rate in high cfDNA concentration group was significantly lower than that in cfDNA low concentration group[(38.6±9.8)% vs.( 71.7±8.2)%, P=0.001]. After 6 cycles of chemotherapy, EFS rate in the PHOX2B positive group was significantly lower than that in the negative group [(16.7±14.4)% vs.( 60.6±6.6)%, P=0.014]; which was significantly lower in the Metaiodobenzylguanidine (MIBG) positive group than that of the negative group[(35.2±11.7)% vs.(65.8±7.1)%, P=0.037]. The MYCN gene and cfDNA concentration were not correlated with the prognosis of high-risk NB.Survival analysis of the combination of PHOX2B and MYCN gene ( PHOX2B+ /MIBG + , PHOX2B+ or MIBG + , PHOX2B-/MIBG -) showed a significant difference in the survival among three groups[0 vs.(53.6±1.2)% vs.(65.5±7.4)%, P=0.003]. Conclusions:The MYCN and PHOX2B gene and cfDNA concentration are of significance in risk stratification and predicting the prognosis of high-risk NB.Compared with the MYCN gene and cfDNA concentration, the PHOX2B gene is more suitable for monitoring the curative effect of chemotherapy on high-risk NB.A combined analysis of PHOX2B gene and MIBG before treatment can be more accurate in evaluating the treatment effect and residual lesions.
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Objective To investigate the effects of 13-cis retinoic acid (13-cis RA) in inducing differentiation of 3 types of human neuroblastoma (NB) cells in vitro.Methods The status of MYCN gene amplification of cultured SH-SY5Y,SK-N-SH and SK-N-BE2 cells was detected by fluorescence in situ hybridization.After treatment with different concentrations of 13-cis RA,morphological changes were observed by phase-contrast microscope,and neuron-specific enolase (NSE) concentrations were determined by enzyme linked immunosorbent assay.The cell viability was measured through cell counting kit-8 assay,and the cell apoptosis was assayed with flow cytometry (FCM).Results The morphological changes in differentiation were observed in all 3 types of NB cells after 13-cis RA treatment.MYCN amplification was detected in SK-N-BE2 cells even after 13-cis RA treatment,while the other 2 cell lines were amplification-null.After different concentrations of 13-cis RA treatment,NSE concentration increased with prolonged time,especially for SK-N-BE2 cell(F =27.00,P ＜ 0.000 1).13-cis RA stimulated cell proliferation within 48 hours of treatment,and then inhibited cell growth.FCM indicated that the degree of apoptosis in SH-SY5Y cell was significantly higher after 13-cis RA treatment of 10 μmol/L concentration for continuous 96 h and 120 h as compared to the control group (F =16.21,P =0.011;F =16.04,P =0.016).Cell apoptosis of SK-N-SH cell after 13-cis RA treatment of 1 μ mol/L and 10 μ mol/L concentration for 48 h,were significantly higher than those of the control group (F =15.05,P =0.012;F =31.18,P =0.005);while SK-N-BE2 cell with different concentrations of 13-cis RA(1 μmol/L,5 μmol/L,10 μ mol/L) for 120 h were significantly higher than those of the control group(F =9.05,P =0.030;F =11.38,P =0.028;F =7.88,P =0.041).Conclusions The present study showed that 13-cis RA could induce differentiation of human NB ceils in vitro.It induces cell proliferation within 48 hours of 13-cis RA,and thereafter suppresses cell growth.No improvement was found in MYCN amplification cells with the detection of DNA level after 13-cis RA treatment,which suggests that combined treatment is possibly needed.
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Objective To identify the effect of arsenic trioxide (As2O3) on the differentiation and apoptosis of different types of neuroblastoma(NB) cell lines.Methods The cell lines [SK-N-SH,SK-N-BE2,SH-SY5 Y] were induced with different concentrations (0 μmol/L,1 μmol/L,3 μmol/L,5 μ mol/L and 7 μ mol/L) of arsenic trioxide for 24 h,48 h,72 h under the same conditions.The expression of MYCN gene was examined by fluorescence in situ hybridization assay in SK-N-BE2,cell proliferation,cell cycle and cell apoptosis were detected with cell counting kit-8 (CCK-8) assay and flow cytometry.Results 5 μmol/L of As2O3 inhibited the expression of MYCN gene in SK-N-BE2;CCK-8 assay indicated that As2O3 inhibited the proliferation of NB cell in a dose-and time-dependent manner,the cell proliferation was significantly suppressed compared with the low concentration (1 μ mol/L) after treated with As2O3 by 1 μmol/L,3 μmol/L,5 μmol/L and 7 μmol/L in 24 h,48 h and 72 h,SH-SY5Y:24 h(chisq =9.666 7,P ＜ 0.05),48 h (chisq =9.666 7,P ＜ O.05),72 h (chisq =9.512 8,P ＜ 0.05);SK-N-SH,24 h (chisq =10.38,P＜0.054 6),48 h(chisq=8.641 0,P＜0.05),72 h(chisq=9.461 5,P＜0.05);SK-N-BE2:24 h (chisq =8.435 9,P ＜0.05),48 h(chisq =8.641 O,P ＜0.05),72 h(chisq =9.545 5,P ＜0.05);compared with the control group,the As2O3-treated cells showed increased apoptosis percentage,with the percentage of 1.6％ (0 μmol/L),3.8％ (1 μmol/L),6.1％ (3 μmol/L),10.4％ (5 μmol/L),40.2％ (7 μ mol/L);the cell cycle was arrested at G2/M phase,which prevented cell division.Conclusions (1) As2O3 play an important role on the NB cells proliferation,apoptosis which were dose-and time-dependent manner.(2)As2O3 can inhibit the expression of MYCN gene.(3)As2O3 also could block NB cell cycle at S and G2/M,and inhibit the cell nucleus replication and the As2O3 had different induced effect between different types of NB cell.
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Objective To explore the significance of MYCN gene amplification in children with neuroblastic tumors(NT).Methods The clinicopathological data of 154 cases with NT were reviewed,including general data, classification of pathology,clinical stage and prognosis.MYCN gene amplification was detected by fluorescence in situ hybridization(FISH) and its relationship between pathological characteristics and prognostic significance was analyzed.Results There was 154 cases of NT aged 1 day to 11 years,with a mean age of 26.1 months,and the median age of 20.5 months.Male and female ratio was 1.48 : 1.00.According to International Neuroblastoma Staging System (INSS) ,20 cases were of stage Ⅰ (13.0％) ,23 cases of stage Ⅱ (14.9％) ,43 cases of stage Ⅲ (27.9％) ,64 cases of stage Ⅳ(41.6％) and 4 cases of Ⅳs (2.6％).There were 72 cases(46.8％) with favorable histology,and 82 cases(53.2％) with unfavorable histology.MYCN amplification was found in 20 cases (13.0％) and the signal ratio of MYCN and chromosome 2 (CEP2) was 4.08-43.29.One hundred and thirty-four cases of MYCN non-amplification included MYCN gain in 91 cases(68.0％) ,MYCN negative in 43 cases(32.0％).MYCN expression showed the significant differences in ages, neuroblastoma type, international neuroblastoma pathology classification (INPC), mitosis karyorrhexis index (MKI), and clinical stages (all P ＜ 0.05).No significant difference was found in gender(P ＞ 0.05).Of 20 MYCN amplification cases,4 cases (20.0％) survived and 16 cases (80.0％) died,and the overall survival rate was 20.0％ (4/20 cases) ,with survival time was (17.10 ± 2.24) months;of 134 MYCN non-amplification cases,96 cases (71.6％) survived and 38 cases (28.4％) died, with survival time of (28.71 ± 1.28)months.Survival analysis showed the cases with MYCN amplification had worse prognosis (x2 =19.596, P ＜ 0.05).Conclusions Patients with MYCN amplification had poorer prognosis and lower incidence of MYCN amplification of pediatric NT was found in China.
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Although the incidence of malignant solid tumors in children is not high,it is one of the major death causes in children.MYCN gene amplification is an independent poor prognosis factor of neuroblastoma.MYCN gene involves in neuroblastoma tumorgenesis and is the major evidence of treatment.MYCN gene amplification could be detected in other children's solid tumor.It is associated with unfavorable medulloblastoma pathology,poor outcome of Wilms' tumor and alveolar rhabdomyosarcomas.This review compares different MYCN gene detection methods,makes a summary about the clinical relationship between MYCN gene and children's solid tumor and investigates the possibility of increasing cure rate of malignant solid tumors through molecular specificity treatment.