Cloning and expression of pokeweed antiviral protein gene from Phytolacca americana in Pichia pastoris and the study of apoptosis of human neuroglioma cells U251 induced by recombinant PAP / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To clone the pokeweed anti-viral protein (PAP) gene, to express it in Pichia pastoris, and to study the inhibitory effect of PAP on U251 in vitro.</p><p><b>METHODS</b>The cDNA sequence encoding PAP was cloned by Real-time PCR from Phytolacca americana. The recombinant PAP was subcloned into the expression vector pPICZaA and expressed in Pichia pastoris GSI15 after methanol induction. SDS-PAGE analysis showed that the expressed PAP existed in the yeast culture supernatant. The drug cytotoxicity to U251 cells was assessed using MTT assay and the obvious apoptotic nuclei of the tumor cells detected using the method of single cell gel electrophoresis.</p><p><b>RESULTS</b>The full-length PAP gene was cloned. The recombinant expression plasmid pPICZaA-PAP was constructed successfully. SDS-PAGE analysis showed that the relative molecular mass (M) of the recombinant protein was about 35 kDa. The degradation of the genome of the apoptotic cells induced by PAP was detected using the method of single cell gel electrophoresis. PAP possessed very high ability to inhibit the growth of U251. The anti-tumor activities (IC50) to U251 cells of PAP was 81.0 microg/mL.</p><p><b>CONCLUSION</b>PAP could be a potent anti-tumor candidate for inhibiting the growth of U251 and inducing its apoptosis.</p>

Generation of cytotoxic T lymphocytes specific for B-cell acute lymphoblastic leukemia family-shared peptides derived from immunoglobulin heavy chain framework region / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Immunoglobulin heavy chain variable region (IgHV) is a well-characterized tumor antigen for B-cell malignancies. It can function as a target for T cell-mediated immune response. Clinical trials of IgHV protein vaccines against lymphoma have demonstrated induction of tumor-specific cytotoxic T lymphocyte (CTL) responses. However, complementary determining regions-based individual vaccines have disadvantages for wide clinical application. Although a recent study demonstrated that immunogenic peptides are derived from framework regions (FR) shared among patients with B-cell lymphoma, how to choose the appropriate peptides for each patient is still unsolved. The aim of this study was to investigate whether immunoglobulin heavy chain FR-derived peptides shared in each IgHV family are potential CTL epitopes presented by B-cell acute lymphoblastic leukemia (B-ALL). Such CTL epitopes might be beneficial to shifting vaccination strategies against B-ALL from individual specificity to family specificity.</p><p><b>METHODS</b>Seven IgHV gene families were amplified respectively by PCR and sequenced directly from 71 childhood B-ALL cases. Bioinformatics was applied in analyzing characteristics of sequences available and predicting HLA-A*0201-restricted CTL epitopes for each IgHV family. An antigen-specific T cell expansion system was used to generate peptide-specific CTLs. The cytotoxicity of CTLs against B-ALL cells was assessed in the lactate dehydrogenase release assay.</p><p><b>RESULTS</b>Complete IgHV rearrangements were identified in all of the 71 B-ALL cases. All of 40 sequences available showed > or = 98% homology with the nearest germline IgHV genes, indicating IgHV genes in B-ALL of germline nature. Twelve nonapeptides of high HLA-A*0201-binding scores were obtained from 26 productive IgHV protein sequences. Ten (83%) of the peptides were located in FR1 and FR3 shared among the corresponding IgHV family. CTLs specific for the peptide QLVQSGAEV located in FR1 (3 - 11) shared among the IgHV1 family could be successfully generated from peripheral blood mononuclear cells of two HLA-A*0201 + healthy donors in vitro and were capable of killing HLA-matched B-ALL cell clones belonging to the IgHV1 family.</p><p><b>CONCLUSION</b>Anti-B-ALL CTLs against immunoglobulin heavy chain FR-derived peptides have family-specific cytotoxicity.</p>

Variant fusion transcript in ALL children with E2A-PBX1 fusion gene positive / 中国实验血液学杂志

The study was aimed to investigate the expression of E2A-PBX1 fusion gene in children with acute lymphoblastic leukemia (ALL). The primers located at different sites of E2A and PBX1 gene were used to screen for the fusion gene in 410 children with ALL, including 362 cases of B cell ALL and 48 cases of T cell ALL. The results showed that 17 children carried the fusion gene. The positive rate was 4.1%. Furthermore, all the positive cases expressed a variant type of fusion transcript. It resulted from different splicing of the 13th exon (159 bp) of E2A gene. Analyses with BLASTn indicated that the variant type of transcript retained the open reading frame. However, the loss of 53 amino acid residues which were located at the 2nd activation domain resulted in the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat. It is concluded that all the children with ALL positive for the E2A-PBX1 fusion gene express typical and variant fusion transcripts. The latter resulted from different splicing of the 13th exon (159 bp) of E2A gene. The loss of 53aa would lead to the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat.

Relationships between thiopurine methyltransferase gene polymorphisms and its enzymatic activity / 中华肿瘤杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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).</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

A retrospective study on enzyme replacement therapy in patients with Gaucher disease / 中华儿科杂志

<p><b>OBJECTIVE</b>Gaucher disease is the most common lysosomal storage disorder. A deficiency of beta-glucocerebrosidase causes accumulation of the glucocerebroside in macrophages throughout the body. This study summarizes the effects of enzyme replacement therapy (ERT) with Imiglucerase in children with Gaucher disease.</p><p><b>METHODS</b>Data from 72 patients (46 were male and 26 female, age ranged from 16 months to 22 years, median 8 years and 8 months) who were treated in the hospital between May 1999 and October 2005 were collected and analyzed, 57 of the patients had type 1 Gaucher disease, 2 patients with type 2, and 13 patients with type 3. Twenty-two patients had undergone total splenectomy. Imiglucerase was given at an initial dose 60 U/kg body weight by intravenous infusion every 2 weeks. The dose was reduced to 45 U/kg when they had achieved the specified therapeutic goals after 2 years. Clinical outcome data of Imiglucerase treatment were collected using routine Gaucher clinical measures, including growth, hematology, liver and spleen 3-dimensional measurements, and skeletal assessments every 3 - 6 months.</p><p><b>RESULTS</b>Three patients were lost to follow-up, 4 patients died, and 65 patients continued to receive the therapy. Hemoglobin and platelet levels of the patients with intact spleen increased most rapidly from the first 12 months of ERT (P < 0.01). Hemoglobin level of the patients who had undergone splenectomy determined at 30 months of treatment was higher than that of baseline (P < 0.01), but platelet levels were not significantly different (P > 0.05). The volumes of the liver decreased after the 6 months of ERT, decreased in average by (39 +/- 17)% at 24 months (P < 0.01). The volumes of spleen decreased after the 12 months of ERT by (59 +/- 21)% at 24 months (P < 0.01). During the first 12 month, the height and weight of the patients who were 2 - 12 years old increased (8.6 +/- 4.3) cm and (2.6 +/- 1.7) kg, respectively, and those of the patients who were 12 - 18 years old increased (5.2 +/- 3.9) cm and (4.5 +/- 3.3) kg, separately. Bone pain reported by 16 patients relieved after 3 months of treatment. But radiological evidence of bone disease did not change. The signs and symptoms of CNS involvement in patients with type 2 and type 3 disease were not improved. No serious adverse events were reported.</p><p><b>CONCLUSIONS</b>ERT with Imiglucerase could improve the quality of life of the patients with Gaucher disease by ameliorating the Gaucher disease-associated anemia, thrombocytopenia, organomegaly, growth retardation and bone pain.</p>

Epitopes recognized by cytotoxic T lymphocytes in immunoglobulin heavy chain variable regions expressed by B-cell acute lymphoblastic leukemia / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To clone IgHV genes from childhood B-ALL cells and identify CTL epitopes deduced from IgHV gene.</p><p><b>METHODS</b>Seven IgHV gene families were respectively amplified by PCR and directly sequenced for 37 childhood B-ALL cases. Bioinformatics were applied for analyzing characteristics of sequences available and predicting HLA-A*0201 molecule-binding nonapeptides derived from IgHV. The predicted nonapeptide QLVQSGAEV was synthesized and its binding affinity to T2 cells determined. CD8+ T cells from a healthy HLA-A*0201+ donor peripheral blood were stimulated repeatedly with QLVQSGAEV-loaded antigen presenting cells.</p><p><b>RESULTS</b>IgHV gene rearrangements were identified in 37 B-ALL. Forty IgHV gene sequences available preferentially utilized V(H)4-59 and V(H)4-34 gene segments. Increased frequency (15.4%) of D7-27 in B-ALL IgHV was found compared to that reported for adult PBLs (P = 0.02); 20.0% DJ(H) junctions in B-ALL lacked non-encoding nucleotides, a frequency higher than that reported for adult PBLs (P = 0.02). 17.5% B-ALL IgHV contained < 2% replacement mutations. Forty B-ALL IgHV sequences acquired 12 high HLA-A*0201-binding nonapeptides, 10 (83.0%) peptides were located in frame region (FR)1 and 3. The synthesized peptide QLVQSGAEV up-regulated HLA-A*0201 expression 1.63 fold on the surface of T2 cells. The frequency of QLVQSGAEV-specific CD8+ T cells in a healthy HLA-A*0201+ donor peripheral blood increased from 1.6% and 82.6% after two-round and 3-round stimulations, respectively.</p><p><b>CONCLUSION</b>IgHV genes in childhood B-ALL are of germline characteristics. Their heavy chain framework regions contain HLA-A*0201-binding nonapeptides. These peptides are capable of inducing specific CD8+ T cells to activate and proliferate.</p>

Induction of anti-B-cell acute lymphoblastic leukemia cytotoxic T lymphocyte response against immunoglobulin heavy chain frame-derived nonapeptide / 中华血液学杂志

<p><b>OBJECTIVE</b>To induce anti-B-cell acute lymphoblastic leukemia (B-ALL) cytotoxic T lymphocyte response against immunoglobulin heavy chain frame-derived nonapeptide.</p><p><b>METHODS</b>The peptide, QLVQSGAEV, containing IgHV1 frame region 3rd-11th amino acids (IgHV1(3-11)), was synthesized. IgHV1(3-11)-T2 binding tests were performed. HLA-A * 0201-positive normal peripheral blood mononuclear cells (PBMNC) were stimulated by IgHV1(3-11)-loaded antigen presenting cells three times at weekly intervals. HLA-A * 0201/IgHV1(3-11) tetramers were used to detect the proliferation of IgHV1(3-11)-specific CD8(+) T cells in the culture. Seven IgHV gene families of B-ALL patients were respectively amplified by PCR and the PCR products were sequenced to select IgHV1 and IgHV3 family monoallelic functional rearrangements. Among them, HLA-A * 0201 positive individuals were subsequently identified. Cytotoxicity of IgHV1(3-11)-specific CD8(+) T cells against HLA-A * 0201-positive IgHV1/IgHV3 family B-ALL cells was measured by MTT assay.</p><p><b>RESULTS</b>The synthesized IgHV1(3-11) up-regulated HLA-A * 0201 expression on T2 cell surface by 1.63-folds. The percentage of IgHV1(3-11)-specific CD8(+) T cells in HLA-A * 0201-positive normal PBMNC was increased from 1.64% after second stimulation to 82.57% after third stimulation. At effector: target ratio of 20:1, the killing rate of IgHV1(3-11)-specific CD8(+) T cells against IgHV1 family B-ALL cells was 18.24%, being 1.8-folds as that against IgHV3 family B-ALL cells (P = 0.01).</p><p><b>CONCLUSION</b>Cytolytic T lymphocytes generated in vitro against immunoglobulin heavy chain frame-derived nonapeptides can kill B-ALL cells expressing these peptides.</p>

Characteristics of immunoglobulin heavy chain variable region genes in childhood B-cell acute lymphoblastic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the origin of childhood B-cell acute lymphoblastic leukemia (B-ALL) and its epitopes recognized by cytotoxic T lymphocytes (CTL) in immunoglobulin heavy chain variable region (IgHV).</p><p><b>METHODS</b>Seven IgHV gene families were respectively amplified by PCR and directly sequenced in 108 childhood ALL. The amino acid sequences were deducted from sequenced nucleotides. Bioinformatics was applied to analyses of recombination patterns, somatic mutations and germline gene segments usage, and to prediction of epitopes recognized by CTL.</p><p><b>RESULTS</b>IgHV gene rearrangements were identified in 66% of the cases, including 37 (52.1%) monoallelic rearrangements, 26 (36.6%) biallelic rearrangements and 8 (11.3%) oligoclonal rearrangements. Among the obtained 40 B-ALL IgHV gene sequences, 8 (20.0%) were in frame rearrangements without stop codons. V(H3) (11/40), V(H4) (11/40) and V(H1) (8/40) amounted to 75% rearranged V(H) families. V(H)(4-59) and V(H)(4-34) were the most frequently rearranged V(H)(4) family gene segments. Usage of D2 and D3 families was most prominent (35.9% and 28.2%, respectively). Increased frequency of D7-27 (15.4%) was found as compared to that of normal peripheral B lymphocytes (P = 0.02). J(H)(6) was found in 47.5% rearrangements followed by J(H)(4) (27.5%). 8/40 (20.0%) DJ(H) junctions lacked N nucleotides, which was higher than that reported for normal peripheral B lymphocytes (P = 0.02). 17.5% B-ALL IgHV contained scattered replacement mutations with replacement (R) to silent (S) substitution ratio (R/S ratio) <or= 1 in complementarity determining region (CDR). Above 80% potential HLA class I molecule-binding peptides were derived from framework regions of immunoglobulin heavy chains in 26 B-ALL cases and 1 - 2 peptides of the same IgHV family were shared by B-ALL.</p><p><b>CONCLUSION</b>B-ALL originated from progenitor or precursor B lymphocytes. B-ALL IgHV genes are of germline characteristics. Potential T cell epitopes were derived from framework regions 1 and 3 of immunoglobulin heavy chain in B-ALL.</p>

Analysis of T cell repertoire in children with acute B lymphoblastic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>The complementarity determining region 3 (CDR3) of T cell receptor (TCR) is the place through which T cells connect to the antigen. The lengths and DNA sequences of CDR3s are different according to different T cell clones. This leads to a diverse TCR CDR3 repertoires which can reflects the functional status of T cells precisely. This study aimed at elucidating the abnormality of TCR beta chain variable region (BV) CDR3 repertoires of children with acute B lymphoblastic leukemia, the pathogenesis of leukemia associated with T cell dysfunction and the immuno-reconstruction of T cells after the chemotherapy.</p><p><b>METHODS</b>Twelve children aged from 3 to 13 years (average 4.50 +/- 3.78 years) with acute B lymphoblastic leukemia before chemotherapy and 8 healthy control donors aged from 6 to 16 years (average 10.30 +/- 3.00 years) were enrolled. Four of 12 patients were studied for the second time 3 months after complete remission (CR). Reverse transcription-polymerase chain reaction (RT-PCR) and polyacrylamide sequencing gel electrophoresis were used to detect the diversity of TCR BV CDR3 repertoires of these children.</p><p><b>RESULTS</b>(1) The expression of BV2 and BV3 in 12 children increased and BV17 and BV18 decreased before the chemotherapy as compared with controls (P < 0.05). There were 4 children with a lower level expression of BV21 before the chemotherapy, and much lower level expression was found after the remission. (2) Normally each lane contained eight to ten bands, which represented unique CDR3 sizes for a given TCR BV family. Bands differed in size by 3 nucleotides and generally form a Gaussian distribution. There were 14% TCR BV families with abnormal CDR3 length distribution in 12 patients before therapy, which was significantly higher than that of controls (5.5%, P < 0.05). Restricted CDR3 length distribution was observed in BV14, BV1, BV16, BV20, BV13.1, BV13.2 and BV6. Every abnormal BV family recovered to normal Gaussian distribution 3 months after CR.</p><p><b>CONCLUSION</b>T lymphocytes in children with acute B lymphoblastic leukemia revealed markedly skewed repertoires, which suggests the abnormality of T cell functions. Most abnormal T cell repertoires recovered to normal Gaussian distribution 3 months after the first CR, which suggests the immunological reconstitution of T cell repertoires.</p>

Association of human leukocyte antigen non-classical genes with type 1 diabetes / 中华儿科杂志

<p><b>OBJECTIVE</b>HLA-DMA and DMB are non-classical genes whose product (DM molecules) plays an important role in antigen presentation. Our present study was designed to investigate the relationship between human leukocyte antigen-DMA, -DMB and clinical status heterogeneity of type 1 diabetes.</p><p><b>METHODS</b>A total of 80 children (male 36, female 44) with type 1 diabetes were selected as research subjects. Diagnosis of type 1 diabetes was made according to WHO criteria. The range of age at onset of type 1 diabetes was 2.5 - 14 years. Ninety-one healthy adult blood donors were selected as normal controls. Polymerase chain reaction and dot blot hybridization techniques were used to classify DMA and DMB alleles. Patients with type 1 diabetes were classified into different groups according to different clinical status, including sex, age of onset, ketosis onset situation on diagnosis, remained function of islet beta cell, etc. Then distribution of DM susceptive alleles and heterodimer in different clinical groups were studied.</p><p><b>RESULTS</b>The frequencies of DMA * 0103 and DMB * 0103 alleles in patients were significantly increased (50% vs. 8%, 43% vs. 22%, respectively), these two alleles confer susceptibility to type 1 diabetes in Chinese. The frequencies of DMA * 0103/DMB * 0102, DMA * 0103/DMB * 0103 and DMA * 0103/DMB * 0101 heterodimers were also increased in the patients. The above heterodimers confer predisposition to type 1 diabetes. Both DMB * 0103 allele and DM susceptive heterodimers are related to islet beta cell function on diagnosis. The patients with DMB * 0103 allele or DM susceptive heterodimers were significantly increased in the patients with lower C-peptide level on diagnosis (56% vs. 29%; 58% vs. 34% respectively). DM heterodimes were also related to onset age and ketosis-onset-situations of the patients. The patients carrying DM susceptive heterodimers had higher probability to suffer type 1 diabetes before 10 years of age and had the predisposition to ketosis or ketoacidosis on diagnosis.</p><p><b>CONCLUSION</b>HLA- class II non-classical alleles-DMA and DMB may play an important role in pathogenesis of type 1 diabetes, and clinical status heterogeneity of type 1 diabetes may be related to genetic mechanism.</p>

Detection of 29 types of fusion gene in leukemia by multiplex RT-PCR / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the fusion genes derived from 29 types of chromosome structural aberrations in children with leukemia.</p><p><b>METHODS</b>Bone marrow samples from 191 children with leukemia were analyzed with a novel multiplex nested RT-PCR.</p><p><b>RESULTS</b>Of the 191 leukemic samples, 86 (45.0%) carried 14 types of fusion genes including SIL/TAL1, MLL/AF1q, E2A/PBX1, MLL/AF6, AML1/ETO, MLL/AF9, TEL/ABL, BCR/ABL, MLL/AF10, dupMLL, MLL/ENL, TEL/AML1, PML/RARalpha and CBFbeta/MYH11. The activation of oncogene HOX11 was detected in 31 cases, with or without other chromosome aberrations in 15 (7.8%) and 16 cases (8.4%), respectively.</p><p><b>CONCLUSION</b>This multiplex nested RT-PCR reaction could screen 29 types of chromosome structural aberrations at the same time. It may be helpful for the detection of minimal residual diseases after chemotherapy and bone marrow transplantation.</p>

Relationship between single nucleotide polymorphisms in thiopurine methyltransferase gene and tolerance to thiopurines in acute leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>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).</p><p><b>METHODS</b>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).</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Exploration of methodology for assay of single nucleotide polymorphism in thiopurine methyltransferase gene / 中国实验血液学杂志

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.