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ABSTRACT: To investigate the clinical manifestations, pathological characteristics and treatment of primitive neuroectodermal tumor/Ewing's sarcoma (PNET/EWS) of the penis in children.
We analyzed the clinical data of a case of PNET/EWS and reviewed relevant literature.
The patient was a 5-year-old boy, admitted for penis swelling with pain for 11 months. Biopsy showed a small round cell tumor, CD99 positive by immunohistochemical staining, with EWS translocation by fluorescence in situ hybridization on molecular biological examination. The tumor was confirmed to be PNET/EWS of the penis, and disappeared after 45 weeks of chemotherapy and local radiotherapy.
PNET/EWS of the penis is an extremely rare disease, with no specific clinical symptoms except penis enlargement with pain. Immunohistochemistry and molecular biological examination contribute to its diagnosis.
Zhonghua nan ke xue = National journal of andrology 12/2012; 18(12):1115-8.
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ABSTRACT: This study was purposed to analyze the relation of N-myc gene copy number with clinical staging, pathological types and tumor biological factors in children with neuroblastoma (NB), and to investigate the influence of chemotherapy on N-myc gene expression and explore the relationship of N-myc gene copies with progrosis of NB children. The newly diagnosed children with NB from 1 March 2007 to 31 January 2011 were enrolled in this study. The treatment was carried out by BCH-NB-2007 based on Hongkong NB-07 protocol, and the patients were follow up to 31 January 2012. The N-myc gene in NB children was detected by FISH. According to number of N-myc gene copies, the NB children were divided into 3 groups. A group (N-myc gene negative) had less than 2 copies, B group (N-myc gene gains) had 3 to 9 copies, and C group (N-myc amplification) had more than 10 copies. The results showed that the N-myc gene expression in 58 cases of NB was observed. There were 36 males and 22 females. NB children aged from 6.5 to 138 months (median age 47.5 months), all patients were followed up for 11 - 57 months with an average of 31.5 months. INSS stages I-IV were 1, 5, 8 and 44 cases, respectively. Twenty-five cases had primary postmediastinal tumor, thirty-three cases had retroperitoneal and pelvic tumor, three of which also companied with postmediastinal tumor. Thirty-five cases had bone metastasis (60.3%), thirty-two cases had bone marrow metastasis (55%). Of the 54 patients with fully known biologic features, seventeen cases had ganglioneuroblastoma, thirty-seven cases had neuroblastoma (15 displayed differentiated, 7 poorly differentiated or undifferentiated, 15 with pathological changes after chemotherapy), four cases had bone marrow metastasis only detected by bone marrow biopsy. Eleven cases had N-myc gene negative, forty-three had N-myc gains, four had N-myc amplification. The average copy number of N-myc gene copies in 58 cases was 5.96 ± 7.81 in which 28 children were non chemotherayp cases, their average copy number was 4.00 ± 1.88, thirty cases out of 58 cases received preoperation chemotherapy (chemotherapy group), and their average copy number was 7.80 ± 10.46, the difference is significant (P = 0.064). The clinic stage, the location of primary tumor, pathological classification, urine VMA and serum neurogenic specific enolase had no effects on the N-myc gene expression, but the serum LDH level had inflnence (P < 0.01). Single factor Kaplan-Meier analysis showed that the number of N-myc gene copies in NB patients were closely related with the poor prognosis. The more copies of N-myc gene, the more poor prognosis, the difference is statistically significant (P < 0.05). It is concluded that the number of N-myc gene copies correlates with the rapid growth of NB and its poor prognosis, detecting the N-myc amplification can help to estimate the prognosis and decide the program of treatment. Serum LDH, which correlated with the rapid growth of NB, had effect on the N-myc gene expression and is closely related with the poor prognosis of NB.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 11/2012; 20(6):1447-51.
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ABSTRACT: This study was aimed to analyze the thiopurine S-methyltransferase (TPMT) gene sequence in acute lymphoblastic leukemia (ALL) children severely intolerant to 6-mercaptopurine (6-MP) and to investigate the causes resulting in tolerance difference to 6-MP in ALL children so as to provide evidence for safe and rational use of 6-MP. The adverse reactions of drug was evaluated in ALL children treated with BCH-2003-ALL chemotherapeutic protocol during 2004-10-1 to 2007-9-30 according to NCI-CTC V2.0. The TPMT gene sequences of ALL children with 3-4 grade of severe toxicity during the maintenance therapy were analyzed by PCR and direct DNA sequencing. To assure the accuracy of sequencing, the 738 bp fragment of coding region in TPMT gene (NM_000367) was divided into 3 subfragments and bidirectionaly sequenced. The results indicated that among 133 ALL children, 61 were severely intolerant to 6-MP. The direct DNA sequencing showed that among 59 patients (excluding 2 cases without RNA samples), the simple myelotoxicity was found in 37 cases, hepato-myelotoxicity was observed in 9 cases, hepatotoxicity along appeared in 12 cases, 1 case showed skin rash. Out of 59 ALL children, the C474T mutation was found in 57 cases, with mutation rate 96.6%, including 21 cases with heterozygous mutation and 36 cases with homozygosis mutation. The TPMT gene sequencing of 10 cases tolerant to 6-MP indicated that C474T mutation was detected in 8 cases which was homozygous mutation. It is concluded that the C474T mutation in 738 bp fragment of coding region in TPMT gene is very frequent, but it is not related with tolerance to 6-MP, suggesting that severe intolerance to 6-MP in ALL children may be not related with the mutation of coding region in TPMT gene.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 07/2012; 20(4):876-9.
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ABSTRACT: IFNλR1 is a member of the class II cytokine receptor family, and it associates with IL-10R2 to form a functional receptor complex, IFNλR. This receptor complex transduces signals from IFNλs (IFNλ1, IFNλ2, and IFNλ3), promoting antiviral and antiproliferative activities similar to those of type I IFNs. In an effort to further understand signal transduction through IFNλR1, we used bioinformatics analysis and identified a tumor necrosis factor receptor-associated factor 6 (TRAF6)-binding motif in the intracellular domain of IFNλR1. In subsequent immunoprecipitation and GST pull-down assays, IFNλR1 was shown to immunoprecipitate with TRAF6 and was pulled down by GST-TRAF6. Endogenous IFNλR1 and TRAF-6 interaction implies that these proteins really interact in the cells. This interaction was abrogated upon mutation of the TRAF6-binding motif in IFNλR1. Furthermore, the interaction between IFNλR1 and TRAF6 inhibited TRAF6-induced NF-κB activation, likely due to a reduction in TRAF6 autoubiquitination. Moreover, co-expression of IFNλR1 with TRAF6 significantly increased the stability of IFNλR1, thereby prolonging its half-life and enhancing its steady-state level in cultured cells. J. Cell. Biochem. 113: 3371-3379, 2012. © 2012 Wiley Periodicals, Inc.
Journal of Cellular Biochemistry 05/2012; 113(11):3371-9. · 2.87 Impact Factor
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ABSTRACT: Clinical categories of Langerhans cell histiocytosis (LCH) include single and multi-system disease. Pulmonary LCH is rare, which is an unusual interstitial lung disease with the characteristics of monoclonal proliferation and infiltration of Langerhans' cells to organs. We report our experience of a rare LCH case of multiple organs such as pulmonary and liver as the main clinical manifestation. The patient was treated with chemotherapy which included prednisone, vinblastine, methotrexate and 6-mercaptopurine for 52 weeks and follow up all along. The patient has a favorable clinical outcome.
Chinese medical journal 05/2012; 125(9):1675-6. · 0.86 Impact Factor
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ABSTRACT: To study the clinical features of childhood acute promyelocytic leukemia (APL) and to analyze the survival and prognostic factors and efficacy and safety of combined treatment with all-trans retinoic acid (ATRA) and anthracycline.
The clinical features of 37 children with newly diagnosed APL hospitalized in our center during January 2005 to February 2009 were retrospectively analyzed.
Thirty percent of patients were at low risk, 43% patients were at intermediate risk, 27% patients were at high risk. Sixty percent of patients had DIC. Retinoic acid syndrome (RAS) was present in 2 patients (6%). Death during induction occurred in 3 patients (8%). Complete remission (CR) was achieved in 83.7% of patients. The patients in high risk group had higher risk than those in intermediate and low risk group (P = 0.029). The time to achieve CR was not significantly different (P = 0.612). Idarubicin had no advantage compared with daunorubicin in time to achieve CR (P = 0.628). Survival rates were calculated using Kaplan-Meier statistical method, and 2 years event-free survival (EFS) rate was 81%, the 2-year EFS rate was 100% for low-risk group, 81% for intermediate-risk group, and 60% for high-risk group.
Using combined chemotherapy with ATRA and anthracyclines had the following advantages: high CR rate, high long-time survival rate and low side effect. DIC remained the main complication among patients receiving induction treatment. Initial WBC count and platelet count are important prognostic factors which might be useful in prognostication and treatment planning.
Zhonghua er ke za zhi. Chinese journal of pediatrics 03/2012; 50(3):219-22.
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ABSTRACT: Insulin-like growth factor binding protein-6 (IGFBP-6) is a member of the insulin-like growth factor binding protein family, which has both Insulin-like growth factor-dependent and independent effects on cell growth. In previous studies, we have shown that recombinant IGFBP-6 could be translocated into the cell nucleus. But the effect in the nucleus of IGFBP-6 is not clear. In the present study, we use multiple methodologies including Glutathione S-transferase pull-down assay, co-immunoprecipitation, fluorescence resonance energy transfer to demonstrate that IGFBP-6 can directly interact with thyroid hormone receptor alpha 1 (TRα1) in vitro and in vivo. We also demonstrate that the DNA-binding domains and Ligand-binding domains of TRα1 and N-terminal domains and C-terminal domains of IGFBP-6 are involved in the interaction. This interaction also can block the formation of TR: retinoid X receptor heterodimers. Furthermore, immunofluorescence co-localization studies show IGFBP-6 and TRα1 could co-localize in the nucleus of the cells. Reporter gene experiment shows that IGFBP-6 negatively regulates the growth hormone promoter activity induced by ligand activated TRα1. Moreover, real-time RT-PCR demonstrates that IGFBP-6 could inhibit the osteocalcin mRNA transcription induced by Triiodothyronine (3,3',5-Triiodo-L-thyronine, T3) in osteoblastic cells. Finally, alkaline phosphatase activity was significantly decreased in osteoblastic cells when the cells were transfected with IGFBP-6 in the presence of T3. In conclusion, these studies provide evidence that overexpression of IGFBP-6 suppresses osteoblastic differentiation regulated by TR in the present of T3.
Molecular and Cellular Biochemistry 02/2012; 361(1-2):197-208. · 2.06 Impact Factor
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ABSTRACT: To explore the effect of LRP (leukemia related protein) 16 on insulin resistance in C2-C12 cells and explore its molecular mechanism.
Lipidosome transfection and lentivirus mediated siRNA (small interfering RNA) technology were used to establish LRP 16 overexpression and underexpression cell lines and their corresponding control cell lines. And 2-deoxy-[(3)H]-glucose was used to measure the effect of LRP 16 on insulin-stimulated glucose uptake. The effects of LRP16 on the phosphorylation of IRS (insulin receptor substrate)-1, Akt and the expressions of PI3K (p85), PPAR (peroxisome proliferator actived receptor) γ and GLUT-4 were detected by Western blot. Luciferase was used to study the effect of LRP16 on the transcriptional activity of PPARγ.
Insulin-stimulated glucose uptake decreased to 46% of the control when LRP16 was over-expressed [(4700 ± 97) vs. (10200 ± 347), P < 0.01]. And the insulin-stimulated glucose uptake was 1.73 fold of control when the expression of LRP16 was suppressed in C2-C12 cells [(17600 ± 466) vs (10200 ± 91), P < 0.05]. The overexpression of LRP16 attenuated the insulin-induced tyrosine phosphorylation of IRS-1, the phosphorylation of Akt and the expressions of PI3K (p85), PPARγ and GLUT-4. But it promoted the insulin-induced phosphorylation of IRS-1 at Ser307 in C2-C12 cells. LRP16 decreased the transcriptional activity of PPARγ in a dose-dependent manner. The transcriptional activity of PPARγ decreased to 43% and 27% of the control when the doses of pcDNA3.1-16 were 0.4 µg and 0.5 µg [(76 ± 11) vs (33 ± 9), P < 0.01] and 27% [(21 ± 9) vs (76 ± 11), P < 0.01].
LRP16 gene causes insulin resistance in C2-C12 cells by inhibiting the IRS-1 signaling and the transcriptional activity of PPARγ.
Zhonghua yi xue za zhi 05/2011; 91(20):1408-12.
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Xiao-li Ma,
Bin Wang,
Hai-ying Guo,
Yong-hong Zhang,
Guang-hua Zhu,
Yan-long Duan,
Jing Yang,
Da-wei Zhang,
Ling Jin,
Rui Zhang,
Li Zhang,
Jin Xie,
Min-yuan Wu
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ABSTRACT: 6-Mercaptopurine (6-MP) has been the backbone of maintenance chemotherapy for acute lymphoblastic leukemia (ALL), the response to 6-MP is highly variable, adverse events leading to discontinuation or dose-reduction (children intolerant) of 6-MP occur in many children with ALL. The aim of this study was to investigate the tolerability of 6-MP and to optimize thiopurine use.
The authors evaluated in a prospective manner the tolerance of 6-MP in ALL children from Oct. 1, 2004 to Sept. 30, 2007 who were newly diagnosed in Beijing Children's Hospital, using BCH-ALL-2003 protocols, during the maintenance therapy and followed up to Sept. 30, 2008. All children had a treatment period of at least 3 months for maintenance therapy.
Totally 133 children including 81 boys and 52 girls at median age of 67 months (18 - 188 months), 100% of the patients went into complete remission (CR) on day 33 of induction chemotherapy, and the median time to CR was 26 months (6 - 47 months). All the children had maintenance therapy from 3 to 25 months (mean 13.5 +/- 7.4) and 72(54%) received 6-MP standard doses continuously for total courses, the median daily dose of 6-MP was 46 mg/(m(2).d) 6-MP, their WBC was (3 - 4) x 10(9)/L, ANC (1.5 - 2) x 10(9)/L, they had no severe liver toxicity. In 4 children the dose of 6-MP was increased to 125% because WBC was higher than 6 x 10(9)/L, ANC higher than 3 x 10(9)/L. Sixty one children (46%) had poor tolerability to 6-MP, they experienced adverse events that led to discontinuation (n = 19) or dose reduction (n = 42) of 6-MP, the actual mean dose for the 42 cases was 25 - 30 mg/(m(2).d) and the time to occurrence of toxic effects was 2.5 weeks. Reasons for discontinuation or dose reduction were severe myelotoxicity occurred in 48 children, hepatotoxicity in 12, and skin rash in one.
In this cohort of ALL children, the difference of tolerance to oral 6-MP was obvious, 54% of the children well tolerated 6-MP during the whole course at oral standard dose, and severe granulocytopenia did not occur. However, 46% developed severe granulopenia or hepatotoxicity, the dosage had to be reduced in order to decrease the probability of severe toxicity. It is suggested that standard dose of 6-MP is not always the maximum tolerant dose in some children and inadequate dose may be the cause of therapy failure.
Zhonghua er ke za zhi. Chinese journal of pediatrics 04/2010; 48(4):289-92.
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ABSTRACT: To investigate the intracellular trafficking pathway of fusion protein epidermal growth factor-adenovirus early region 4 open reading frame 4 protein (EGF-E4orf4) internalized via epidermal growth factor (EGF) receptor and its affectivity on extracellular signal-regulated kinase (ERK) phosphorylation.
MDA-MB-231 and BGC823 cells were incubated with fluorescein isothiocyanate-EGF-E4orf4 or EGF at different time points. The specific molecular mark of early endosome or late lysosome was labeled by indirect immunofluorescence, and then colocalization staining was observed using confocal laser microscopy. The levels of ERK phosphorylation were detected by Western blot.
The fluorescent signal of fusion protein EGF-E4orf4 accumulated within the cells and congregated to the perinuclear region. A nucleus localization of the fusion protein was only at MDA-MB-231 cell. Colocalization of EGF-E4orf4 with early endosome/late lysosome was observed. EGF-E4orf4 stimulated ERK phosphorylation, which was most obvious 10 minutes after stimulation, and then gradually attenuated, which was similar to EGF stimulation but with a less decrease.
Internalized EGF-E4orf4 can be slowly degraded via endosome-lysosome pathway. The action features of EGF-E4orf4 are remarkably different between MDA-MB-231 and BGC823 cells, which may help explain the differences in its anti-tumor potency and in the special selectivity toward different tumor cells.
Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae 12/2009; 31(6):674-8.
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ABSTRACT: OBJECTIVE: To study the nuclear localization of insulin-like growth factor binding protein-6(IGFBP-6) in PC-3M cells. METHODS: The two fragments of the nuclear localization sequence (NLS)-deleted IGFBP-6 and the NLS-mutated IGFBP-6 were obtained by overlapping PCR, and then the fragment was inserted into a pEGFP-C1 vector. PC-3M cells were transfected with the expression constructs containing wild-type IGFBP-6 or the two mutants (pEGFP-C1-BP6DeltaNLS and pEGFP-C1-BP6-Mut), and the different distribution of the three EGFP-fusion proteins was observed by confocal laser microscope. The statistical analysis of the ratio of the nuclear fluorescence to the cytoplasmic fluorescence (Fn/c) was performed. Results Confocal microscopic images of transfected cells showed that the green fluorescence of EGFP-IGFBP-6 was concentrated mostly in the nuclei, whereas the control cells expressing EGFP showed green fluorescence distributed uniformly. The results of Fn/c from EGFP and EGFP-IGFBP-6 were significant different (P<0.05). The NLS-deleted IGFBP-6 completely eliminated nuclear accumulation of the green fluorescent signal; in contrast, nuclear accumulation was only slightly reduced for the NLS-mutated IGFBP-6; compared with wild-type IGFBP-6, both mutants were significantly different (P<0.05). Conclusions IGFBP-6 can be translocated to the nucleus in PC-3M cell that is mediated by a putative NLS sequence. Our study provides new evidence for further studies on the insulin-like growth factor-independent activity of IGFBP-6.
Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae 12/2009; 31(6):735-9.
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ABSTRACT: Adenovirus early region 4 open reading frame 4 (E4orf4) protein is a novel cell death factor that selectively induces apoptosis in cancer cells. This study evaluated tumor inhibitory effects of a protein made by fusion E4orf4 and human epidermal growth factor (EGF). EGF was used to ensure the selective targeting of EGF receptor (EGFR)-overexpressing tumor cells. Results showed that EGF-E4orf4 stimulated EGFR phosphorylation in a time- and dose-dependent manner. Confocal microscopy analysis showed both EGF-E4orf4 and EGF could be internalized via EGFR but they had different intercellular trafficking pathways. In vitro study showed that EGF-E4orf4 significantly inhibited the proliferation of BGC823 and in vivo study showed EGF-E4orf4 suppressed tumor growth in a dose-dependent fashion with an inhibition rate of 79% for MDA-MB-231 and 49% for BGC 823 (p < 0.05). No toxic effects were observed in the nude mice with a dose as high as 10 mg/kg of EGF-E4orf4. These results indicated that EGF-E4orf4 could be a potential drug for cancer therapy.
International Journal of Cancer 04/2009; 125(5):1186-92. · 5.44 Impact Factor
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Zhonghua zhong liu za zhi [Chinese journal of oncology] 03/2009; 31(2):128.
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ABSTRACT: To investigate the relationship between the thiopurine methytransferase (TPMT) gene polymorphisms and its enzymatic activity, and to clarify the significance of TPMT activity and gene polymorphisms on individualized therapy with thiopurines.
The TPMT activity and gene polymorphisms were determined in an unrelated population of 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia. The TPMT genotyping assay was based on polymerase chain reaction (PCR), restriction digestion of PCR products, denaturing high-performance liquid chromatography (DHPLC) and SNaPshot sequencing and direct DNA sequencing in the TPMT exon 5 (G238C), TPMT exon7 (G460A) and TPMTexon10 (A719G). Erythrocyte TPMT activity was measured by high-performance liquid chromatography (HPLC).
The frequency of TPMT polymorphism in 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia was low (3.5%), and all the varied alleles were TPMT* 3C (exon 10A719G). All of them were TPMT* 1/TPMT* 3C heterozygote. The TPMT activity was between 6 and 12 U. The activity in 95.1% was more than 12 U (13 - 32 U), while the activity in others (4.9%) was 6 - 12 U. TPMT activity and genotype were concordant. Of 630 subjects evaluated, TPMT activity of heterozygous individuals in Chinese healthy blood donors, cords blood and acute leukemia patients were 9.1 U, 9.3 U and 9.07 U, respectively, significantly lower than that in general population (17.6 U, 17.67 U and 18.6 U, respectively). In the samples analyzed, ten subjects with heterozygous phenotypes (6/15 acute leukemia children and 4/16 healthy blood donors and cords blood) did not have TPMT* 2, TPMT* 3A or TPMT* 3C. Therefore, other factors may affect on TPMT activity.
TPMT gene polymorphisms and its activity were concordant. The heterozygotes had low TPMT activity. Therefore, detection of TPMT genotype and its activity is useful. These findings hold a promise of improving the safety and efficacy of thiopurines therapy.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 07/2006; 28(6):456-9.
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ABSTRACT: Adenovirus early region 4 open reading frame 4 (E4orf4) protein is a novel cell death factor that selectively induces p53-independent apoptosis in cancer cells, but not in normal human cells. This study presents an approach for inhibiting p53-deficient tumor cell growth by using protein-based E4orf4 that had been genetically fused to epidermal growth factor (EGF) to ensure selective targeting of EGF receptor-overexpressing tumor cells. EGF-E4orf4 enables binding onto the cell surface and is then internalized into Saos-2 cells. The success of the process had been demonstrated by immunofluorescence assay and confocal laser microscopy. After prolonged exposure, E4orf4 remained mostly in the nuclei. EGF-E4orf4 treatment of Saos-2 cells showed dose-dependent cytotoxicity. Nearly 50% of the Saos-2 cells were killed at a concentration of 250 nmol/l. In contrast, EGF-E4orf4 showed no significant inhibitory effect iresn primary cells of human umbilical vein endothelial cells. To confirm the ability of EGF-E4orf4 to induce apoptosis, DNA fragmentation was detected using BrdUTP end-labeling. Flow cytometric analysis revealed a significant increase of apoptotic cells in Saos-2 cells treated with EGF-E4orf4, but not in the case of cells cultured in plain medium (t=0.028, P<0.05). In conclusion, these preliminary results indicate that EGF-E4orf4 could show promise as a new reagent that is more efficient and less toxic in anti-cancer therapy.
Anti-Cancer Drugs 06/2006; 17(5):527-37. · 2.41 Impact Factor
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ABSTRACT: For the purpose of clarifying the influence of thiopurine methyltransferase (TPMT) gene single nucleotide polymorphisms (SNPs) on the efficacy of thiopurines and risk for its toxicity and therefore improving the safety and efficacy of thiopurines, the authors investigated TPMT genotype in acute leukemia in children who were intolerant to the treatment with 6-mercap topurine (6-MP).
TPMT genotype was determined in an unrelated population of 250 Chinese healthy blood donors and 280 children with acute leukemia. TPMT genotyping assay was based on polymerase chain reaction (PCR), restriction digestion of PCR products, denaturing high-performance liquid chromatography (DHPLC) and direct DNA sequencing in the TPMT * 2 (G238C), TPMT * 3A (G460A, A719G) and TPMT * 3C (A719G).
There were 10 TPMT * 1/TPMT * 3C heterozygotes in 280 children. The frequency of the polymorphism was 3.6%. All the involved alleles were TPMT * 3C. Of the 160 children acute leukemia evaluated, 45 (26%) were intolerant to 6-MP. Presentations included hepatotoxicity and hematological toxicity. Six out of 45 children were heterozygous, while the other 39 were wild type homozygous. Before dosage adjustments for thiopurine, the hematologic toxicity and hepatotoxicity in TPMT heterozygous individuals occurred more frequently than in homozygous. Therefore, cases of TPMT heterozygotes experienced more missed doses of 6-MP.
TPMT genotype is associated with tolerance in acute leukemia in children. The heterozygote individuals have low TPMT activity. Therefore the frequencies of hemtopoietic toxicity and hepatoxicity are high after using 6-MP. Detection of SNPs in the TPMT genes is useful in identifying children before administration of 6-MP.
Zhonghua er ke za zhi. Chinese journal of pediatrics 01/2004; 41(12):929-33.
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ABSTRACT: The aim of the present study was to gain an insight into the thiopurine methytransferase (TPMT) genotyping assay, which was based on polymerase chain reaction (PCR), allele-specific PCR, restriction digestion of PCR products, denaturing high-performance liquid chromatography (DHPLC) and SNaPshot sequencing and in combination with direct DNA sequencing. Among the f our methods to test TPMT genetic SNPs based on PCR, allele specific PCR was not able to differentiate wild type from varied type. BsiYI, MwoI and AccI to digest PCR products were used so that SNP in TPMT exon 5, 7 and 10 tested. It showed that there were no differences between the results of digestion of PCR products and those of DNA sequence analysis. Therefore, this method was reliable. But some other methods were still needed to look for a compensation, because no restriction map changing resulted from the 2 SNPs in TPMT promotor was found. As to the results of DHPLC, those for the screening of TPMT exon-5 and -10 for SNPs were the same as restriction analysis of PCR products and direct DNA sequencing. But the variation of the heterozygotes in exon-7 was high, which was different from the results of direct DNA sequencing. After changing the Tm of DNA step by step, It was found that all the samples showed single peak when the temperature was 54 degrees C. But this result was unbelievable because a heterozygote in exon 7 as positive control could not be found. Therefore, it was necessary to test the sensitivity and accuracy of DHPLC, though DHPLC could be used as an effective method of SNPs screening. The results of the SNaPshot sequencing were also same as those of restriction analysis of PCR products and direct DNA sequencing. And the results showed that the bases of TPMT promoter -91 and -168 were G, instead of A and T. The results of the four methods to detect TPMT genetic SNPs based on PCR showed that SNPs analysis technique should be a combination of the techniques above-mentioned. One technique alone could not satisfy the need in clinics and research. The compensation of each other was very important.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 10/2003; 11(5):458-63.
