结直肠癌患者TSER多态性与5-Fu为基础方案化疗疗效关系

[目的]研究胸苷酸合成酶增强子(TSER)多态性与晚期结直肠癌患者以5-Fu为基础方案化疗疗效关系。[方法]收集经病理学确诊的晚期结直肠癌患者59例,化疗前抽静脉血,提取白细胞,用PCR技术检测TSER基因型。所有患者均经FOLFOX4方案治疗,以肿瘤化疗疗效评价标准(WHO)评价疗效。[结果]3R/3R、2R/2R+2R/3R基因型组化疗的有效率分别为19.4%(7/36)、47.8%(11/23),3R/3R与2R/2R、2R/3R两组对5-Fu为基础方案化疗疗效关系存在显著差异性(P<0.05)。[结论]晚期结直肠癌患者TSER多态性与5-Fu为基础方案化疗疗效可能存在相关性,基因型检测可能有助于晚期大肠癌的化疗。     

结肠癌组织ERCC1基因多态性与奥沙利铂药敏关系

[目的]探讨结肠癌组织ERCC1密码子118基因多态性与奥沙利铂药敏的关系。[方法]对53例结肠癌患者新鲜标本进行体外肿瘤细胞原代培养,ATP-TCA法检测肿瘤细胞对奥沙利铂的敏感性,PCR法检测肿瘤的ERCC1密码子118基因多态性,分析ERCC1密码子118基因多态性与奥沙利铂敏感性的关系。[结果]奥沙利铂总有效率为34.7%（17/49）。C/C基因组19例,有效10例,无效9例,有效率52.6%;C/T＋T/T基因组30例,有效7例,无效23例,有效率23.3%。ERCC1不同基因型组间对奥沙利铂敏感性存在显著性差异（P〈0.05）。[结论]ERCC1基因多态性与奥沙利铂化疗敏感性相关,ERCC1基因型检测可能有助于预测结肠癌组织对奥沙利铂化疗敏感性。     

MTT 药物敏感试验在指导胃癌及原发肝癌化疗中的作用

 目的　探讨 3- (4,5) -双甲基 - 2 -噻唑 - (2 ,5) -二苯基溴化四氮唑蓝 (MTT)药敏试验法在指导临床胃癌及原发肝癌化疗中的作用。方法　 50例胃癌和 45例肝癌 ,分设对照组。在化疗前接受 MTT药敏试验者 ,根据药敏结果指导化疗 ,对照组胃癌 2 3例 ,肝癌 2 0例 ,凭经验化疗。结果　在胃癌中 MTT敏感组有效率为 82 .6% (1 9/ 2 3) ,MTT耐药组和对照组有效率分别为 0 (0 / 4 )及47.8% (1 1 / 2 3) ,差异有显著意义 ;肝癌 MTT敏感组有效率为 75% (1 5/ 2 0 ) ,MTT耐药组和对照组有效率分别为 0 (0 / 5)及 40 % (8/ 2 0 )有显著差异 (P<0 .0 1 )。本研究体外药敏和体内疗效总符合率胃癌和肝癌分别为 85.2 % (1 9+4/ 2 7)和 80 % (1 5+5/ 2 5)。结论　MTT体外药敏试验在指导临床胃癌及原发肝癌的化疗中 ,具有满意的效果。     

DNA修复酶XRCC1基因多态性与晚期肺癌化疗敏感性的关系研究

目的:研究DNA修复酶XRCC1基因codon194和codon399多态性与肺癌患者对铂类药物为基础的化疗敏感性的关系。方法:收集经病理学确诊的晚期肺癌112例,所有病例化疗前抽静脉血,提取白细胞DNA,用多聚酶链反应-限制性片段长度多态性(PCR-RFLP)分析技术检测XRCC1基因型。所有患者均经铂类药物为基础的化疗方案治疗。结果:(1)在肺癌患者中,XRCC1194Are/Arg、Arg/Trp和Trp/Trp基因型者分别为48例(43·3%)、51例(45·9%)和12例(10·8%);XRCC1399Arg/Arg、Arg/Gln、Gln/Gln基因型者分别为65例(58·0%)、36例(32·1%)和11例(9·8%)。经化疗后,51例患者有效,总有效率45·5%。(2)XRCC1194Trp/Trp基因型者的有效率为75·0%,显著高于Arg/Arg基因型者(37·5%,χ2=5·36,P=0·0206))。前者的化疗敏感性是后者的5倍(95%CI:1·03~27·21)。同时拥有XRCC1194Trp/Trp和XRCC1399Arg/Arg基因型者的有效率为80·0%,显著高于其他基因型者(P=0·0417,OR=5·40,95%CI:0·98~38·90)。结论:XRCC1基因多态性与晚期肺癌对铂类药物为基础的化疗敏感性相关,检测XRCC1基因型可以预测晚期肺癌化疗的敏感性。     

胶滴肿瘤药敏检测技术评价卡培他滨对胃癌体外药敏实验的条件探索

目的采用胶滴肿瘤药敏检测技术(CD-DST)研究在胃癌术后辅助化疗中卡培他滨(CAP)药敏检测的实验条件。方法由于CAP在体外无法由肿瘤细胞直接代谢,本研究采用其代谢产物5'-脱氧-5-氟尿苷(5'-DFUR)评价CAP的药敏检测条件,对5'-DFUR的CD-DST实验条件进行探索。将31例实验组新鲜胃癌组织标本进行CD-DST检测,以未用药物处理组作为对照,分别以1μg/ml奥沙利铂(L-OHP)、0.03μg/ml伊立替康(CPT-11)和5'-DFUR(浓度为3、5、10μg/ml)进行处理,评价其体外有效率(IVS)与临床有效率的一致性,另将34例验证组新鲜胃癌组织标本进行验证。结果5μg/ml的5'-DFUR处理组的高敏感IVS为31%,与研究报道的CAP临床有效率约为30%一致。采用5μg/ml的5'-DFUR对另外34例胃癌标本进行验证,验证组中5'-DFUR(5μg/ml)处理组高敏感IVS为30%,与实验组IVS结果一致。结论在胃癌辅助化疗中,5μg/ml的5'-DFUR为CD-DST法评价CAP药物敏感性的实验条件,其检测结果IVS与临床有效率一致,为临床胃癌患者术后采用CDDST法进行CAP体外药敏实验提供指导。     

高海拔地区 ERCC1 和 TSER 基因多态性与奥沙利铂联合希罗达治疗进展期胃癌的相关性研究

  目的  探讨高海拔地区切除修复交叉互补基因1(excision repair cross-complementation group 1, ERCC1)、胸苷酸合成酶增强子(thymidylate synthase enhancer region, TSER)的基因多态性, 及与奥沙利铂联合希罗达治疗进展期胃癌的相关性研究。  方法  122例进展期胃癌患者入组并行奥沙利铂联合希罗达化疗, 110例患者按要求完成治疗并随访PCR-RFLP检测基因位点的多态性, 分析基因多态性与化疗客观反应率(response rate, RR)和无进展生存(progression-free survival, PFS)的关系。  结果  ERCC1118C/T位点的多态性与奥沙利铂联合希罗达治疗后的RR、PFS期无相关性(P=0.221, P=0.186)TSER基因为2R/2R、2R/3R型患者的RR和PFS期优于3R/3R型(P=0.037, P=0.033)。  结论  高海拔地区, 奥沙利铂联合希罗达治疗进展期胃癌中ERCC1基因多态性与RR、PFS期无相关性, TSER基因多态性与RR。      

胸苷酸合成酶预测胃癌化疗敏感性的研究

目的 探讨胃癌组织中TS的表达及其对胃癌DDP+5-Fu化疗敏感性的预测价值.方法 60例胃癌均接受2个周期DDP+5-Fu化疗.化疗方案:DDP 15～20 ms/(m2·d),静脉滴注,d1～5;5-Fu 375～500 mg/(m2·d),静脉滴注8h,d1～5.间隔4周后,进行第2个周期化疗.采用免疫组织化学S-P法检测胃癌组织中TS的表达.结果 60例胃癌中TS高表达者29例,化疗有效率34.5%(10/29),TS低表达者的化疗有效率为64.5%(20/31),两者比较差异具有统计学意义(P<0.05).结论 胃癌组织中TS表达水平对胃癌DDP+5-Fu化疗的敏感性具有一定预测价值.     

胸苷酸合成酶基因3′-UTR多态性与晚期胃癌化疗敏感性关系的研究

目的:研究胸苷酸合成酶(TS)基因3′-UTR多态性与胃癌对5-FU化疗敏感性的关系.方法:收集经病理学确诊的晚期胃癌106例,所有病例化疗前抽静脉血,提取白细胞DNA,用PCR-RFLP技术检测TS3′-UTR基因型.所有患者均经5-FU为基础的化疗方案治疗.以WHO实体瘤疗效评定标准和毒性评定标准评价疗效和毒性.结果:(1)106例胃癌患者中TS+6/+6bp、+6/-6bp、-6/-6bp基因型频度分别为7.6%、44.3%和48.1%,化疗的总有效率为35.9%.(2)TS+6/+6bp、+6/-6bp、-6/-6bp基因型组化疗的有效率分别为0%(0/8)、40.4%(19/47)和37.3%(19/51).TS-6/-6bp基因型组和+6/-6bp组化疗的有效率均显著高于+6/+6bp组(Fisher双侧精确检验,P值分别为0.0452和0.0404).TS-6/-6bp基因型组Ⅱ度以上毒副反应的发生率高于+6bp/+6bp基因型组,但其差异无统计学意义.结论:TS基因3′-UTR多态性与晚期胃癌对5-FU为基础的化疗敏感性相关.TS基因型检测有助于指导晚期胃癌的化疗.     

MTHFR多态性对晚期胃癌患者化疗作用的预测研究

目的:研究亚甲基四氢叶酸还原酶(MTHFR)基因C677T、A1298C多态与胃癌患者对5-FU为基础的化疗敏感性和毒性的关系。方法:晚期胃癌患者106例,用聚合酶链反应-限定性片段长度多态性(PCR-RFLP)技术检测白细胞DNAMTH-FR基因型。所有患者经5-FU为基础的化疗方案治疗。结果:1)在106例晚期胃癌患者中,MTHFRC677TCC、CT、TT基因型分别占31·1%、46·2%和22·6%;MTH-FRA1298CAA、AC、CC基因型者分别为69·8%、29·2%和0·9%;化疗总有效率35·8%。2)MTHFRC677TTT基因型携带者化疗有效率(83·3%)明显高于C677TCT(24·5%;P=0·000)和C677TCC(18·2%;P=0·000)。而MTHFRA1298CAA组有效率(43·2%)亦明显高于A1298CAC CC组(18·8%,P=0·009)。3)在CFL、CFH、LFP方案治疗的患者中,C677T变异子携带者对化疗敏感性更高。对A1298C多态性,患者接受CFL方案化疗时,1298AA纯合子携带者有效率高于1298CT/CC患者。4)MTHFRC677TTT、CT或A1298CAA多态性携带者化疗相关的恶心/呕吐发生率明显高于其他三种多态性者。结论:MTHFR基因多态性的检测可能是晚期胃癌患者接受5-FU为基础化疗疗效和毒副反应的良好预测指标。     

ATP生物荧光肿瘤体外药物敏感性检测在口腔癌化疗中的应用

目的探讨肿瘤体外药敏实验ATP生物荧光法(ATP-TCA)在口腔癌化疗中的应用。方法应用ATP生物荧光肿瘤体外药物敏感性检测法,检测48例口腔癌组织对6种常用化疗方案的敏感性。结果组织标本的可评估率为92.0%。口腔癌对TAT DDP最敏感,体外有效率为83.3%,其次为5-Fu DDP(75.0%),BLM(54.2%),DDP(60.4%),MTX(45.8%),5-Fu(62.5%)。化疗药物对口腔癌的杀伤作用具有较强的个体差异性。结论TP生物荧光肿瘤体外药物敏感性检测法敏感性高、稳定性好、简便、快速、检测结果可靠,可用于临床制定个体化的化疗方案。     

Polymorphism in the thymidylate synthase promoter enhancer region in colorectal cancer.

Thymidylate synthase (TS) is an important target for chemotherapy drugs such as 5-fluorouracil and raltitrexed. Over-expression of TS has been linked to chemotherapy resistance. A polymorphic tandem repeat sequence in the 5' untranslated region (5'UTR) of the human TS gene (TSER) has been shown to influence TS expression. The presence of a triple tandem repeat (TSER*3) increases in vitro TS expression compared to a double tandem repeat (TSER*2) and is associated with higher in vivo tumor TS activity. The polymorphism of this promoter enhancer region has not been extensively studied in patients with cancer and may represent a possible mechanism of intrinsic resistance to TS inhibitors. In this study, PCR analysis of genomic DNA from 121 patients with colorectal cancer demonstrated 29% of patients were homozygous for TSER*3, 16% were homozygous for TSER*2 and 55% were heterozygous. In 44/45 microdissected tumors the TS enhancer genotype was identical between paired samples of colorectal tumor and normal tissue. In 24 patients receiving a bolus/infusion 5-fluorouracil (5FU) regimen for metastatic colorectal cancer, 22% of non-responders to chemotherapy were homozygous for TSER*2 compared with 40% of responders. Median survival dropped from 16 months for homozygous TSER*2 to 12 months for homozygous TSER*3. This is consistent with previous studies where higher TS expression was associated with poor response to TS inhibitors. Prospective analysis of the influence of the TS polymorphism on patient outcome is warranted.     

Thymidylate synthase 5'- and 3'-untranslated region polymorphisms associated with risk and progression of squamous cell carcinoma of the head and neck.

PURPOSE: Folate deficiency and reduced DNA repair capacity are established risk factors for squamous cell carcinoma of the head and neck (SCCHN). We hypothesized that polymorphisms of the thymidylate synthase (TYMS) gene, which regulates a key enzyme in folate metabolism required for DNA synthesis and repair, are associated with SCCHN risk. EXPERIMENTAL DESIGN: In a hospital-based case-control study of 704 SCCHN cases and 1,085 controls, frequency matched by age, sex, and ethnicity, we genotyped the TSER (thymidylate synthase in the 5'-untranslated enhanced region) and TS3'UTR (thymidylate synthase in the 3'-untranslated region) polymorphisms. RESULTS: The TS3'UTR 0bp/0bp genotype was associated with a significantly decreased risk of SCCHN [adjusted odd ratio (OR) = 0.67, 95% confidence interval (CI) = 0.47-0.94] compared with the 6bp/6bp genotype, but the TSER polymorphism had no main effect on risk of SCCHN. When we evaluated the two polymorphisms together by the number of protective alleles (the TSER 3R and TS3'UTR 0bp alleles), we found that the combined genotypes with four protective alleles (the TSER 3R3R and TS3'UTR 0bp/0bp) was associated with significantly decreased SCCHN risk (OR = 0.60, 95% CI = 0.37-0.98). In addition, the TS3'UTR 0bp genotypes were associated in an allele dose-dependent manner with a decreased risk of overall stage IV oral cancer (OR = 0.84, 95% CI = 0.52-1.34 for the 6bp/0bp genotype and OR = 0.26, 95% CI = 0.08-0.87 for the 0bp/0bp genotype; P(trend) = 0.035). CONCLUSION: The TSER and TS3'UTR polymorphisms are associated with SCCHN risk. The TSER 3R and TS3'UTR 0bp alleles seemed to jointly protect against SCCHN. In particular, the 0bp allele seemed to protect against oral cancer progression.     

Methylenetetrahydrofolate reductase (MTHFR) C677T and thymidylate synthase promoter (TSER) polymorphisms in Indonesian children with and without leukemia

Genetic variations in the polymorphic tandem repeat sequence of the enhancer region of the thymidylate synthase promoter (TSER), as well as in methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, influence methotrexate sensitivity. We studied these polymorphisms in children with acute lymphoblastic leukaemia (ALL) and in subjects without malignancy in Indonesia and Holland. The frequencies of TT and CT genotypes were two-fold higher in Dutch children. The TSER 3R/3R repeat was three-fold more frequent in the Indonesian children, while the 2R/2R repeat was only 1% compared to 21% in the Dutch children. No differences of these polymorphisms were found between ALL cells and normal blood cells, indicating an ethnic rather than leukemic origin. These results may have implications for treatment of Indonesian children with ALL.     

The association of expression and gene polymorphism of the thymidylate synthase gene with 5-fluoro-5'-deoxyuridine sensitivity in gastric cancer cell lines

Thymidylate synthase (TS) is a target enzyme of 5-fluorouracil (5-FU), and the TS expression level of cancer tissues is a potential predictor of the response to 5-FU-based chemotherapy. The TS gene has a polymorphic tandem-repeat sequence, which is associated with its protein expression. Therefore, the TS polymorphism may also be a predictor of the response to 5-FU-based chemotherapy. In this study, we analyzed the TS genotype, TS protein level, and sensitivity to 5-fluoro-5'-deoxyuridine (5'-dFUrd) in 10 human gastric cancer cell lines. TS genotype was classified into 2R-homozygote (2R/2R, n=3), 3R-homozygote (3R/3R, n=5), and 2R/3R-heterozygote (2R/3R, n=2). The cell lines with 3R/3R showed a significantly higher IC50 value compared to those with 2R/2R or 2R/3R genotype. There was no relationship between TS protein level and 5'-dFUrd sensitivity. However, a statistically significant relationship was revealed between them when the subgroup with the genotypes of 2R/2R or 2R/3R was considered (r=0.815, p<0.05). In this subgroup, the cell lines with higher TS protein showed higher IC50 value for 5'-dFUrd, indicating less sensitivity to 5'-dFUrd. An identical relationship between the TS protein level and IC50 was also observed in the subgroup with 3R/3R genotype, although it did not reach statistical significance (r=0.745, p=0.09). These results suggest that the TS gene polymorphism and TS protein level may be independent predictors for 5-FU-based chemotherapy.     

Polymorphisms in the Enhancer Region of the Thymidylate Synthase Gene Are Associated with Thymidylate Synthase Levels in Normal Tissues but Not in Malignant Tissues of Patients with Colorectal Cancer

BackgroundThe enhancer region of the thymidylate synthase (TS) gene (TSER) contains a polymorphic tandem repeat sequence (2 or 3 repeats, 2R or 3R) and a single-nucleotide polymorphism (G > C) within the second repeat of the 3R alleles which might influence TS expression/activity and response to fluoropyrimidines. However, clinical studies in patients with colorectal cancer (CRC) failed to find a consistent relationship between TSER polymorphisms and protein levels as well as with clinical outcome. The analysis of the relationship between TSER genotype and TS mRNA and activity in normal and malignant tissues might explain the previous controversial data and help in the selection of useful markers to predict drug response and/or toxicity.Materials and MethodsTo address this issue, we studied TSER genotype, TS expression, and activity with specific polymerase chain reaction and activity assays (TS catalytic activity and FdUMP binding) in normal (liver, mucosa) and malignant (primary tumor and liver metastasis) tissues from 83 patients with CRC.ResultsNo correlation between TSER genotype and TS mRNA and protein levels was observed in malignant tissues. In contrast, normal tissues harboring one or two 3RG alleles were characterized by higher TS protein levels (2.4-fold; P = .008) and catalytic activity (P < .05) compared with the other TSER genotypes.ConclusionThese results suggest that TSER polymorphisms do not predict tumoral TS levels possibly depending on altered TS regulation in cancer tissues, and might explain the lack of clear correlation with clinical outcome after chemotherapy with fluoropyrimidines. However, the relationship between TS phenotype and TSER genotype in normal tissues warrants further investigations in large-scale prospective studies evaluating TS genotype and fluoropyrimidine tolerability.     

Genotype of thymidylate synthase likely to affect efficacy of adjuvant 5-FU based chemotherapy in colon cancer

Thymidylate synthase [TS, (EC 2.1.1.45)] is the target enzyme in 5-fluorouracil treatment. Recently, the DNA polymorphism of this gene has been found to affect TS protein (pTS) expression. However, no prospective studies have been performed to evaluate the influence of this polymorphism on the clinical efficacy of 5-FU-based adjuvant chemotherapy for colorectal cancer (CRC). In this study, we investigated the genotype of TS and immunopathological findings of pTS in 161 colon cancer specimens from patients who were registered in a prospective adjuvant immunochemotherapy clinical trial. The clinical course and prognosis of these patients were checked after the study had been completed. This study comprised 11 (6.8%) cases of 2R/2R, 40 (24.8%) of 2R/3R, and 110 (68.3%) of 3R/3R genotypes. All of the 2R/2R cases were still alive at the time of analysis although this finding was not statistically significant. In this prospective examination on a randomized controlled trial, the patients with colon cancer of the 2R/2R TS genotype may be good responders to 5-FU-based adjuvant chemotherapy. Furthermore, differences in the proportions of the TS genotypes can account for the interracial differences in the adverse effects of 5-FU-based chemotherapy.     

Loss of heterozygosity at the thymidylate synthase (TS) locus on chromosome 18 affects tumor response and survival in individuals heterozygous for a 28-bp polymorphism in the TS gene.

Thymidylate synthase (TS), the target enzyme of the fluoropyrimidine class of drugs, has a 28-bp repeat polymorphism in the promoter region that has been associated with response of tumors to 5-fluorouracil-based therapy. Patients homozygous for the double repeat (2R/2R) in the TS gene have an overall better outcome from treatment than patients homozygous for the triple repeat (3R/3R). However, due to loss of heterozygosity at the TS locus on chromosome 18 in cancer cells, heterozygous 2R/3R individuals can acquire the 2R/loss or the 3R/loss genotype in their tumors. The purpose of this study was to determine whether the response of colorectal cancer to fluoropyrimidine therapy is associated with the resulting tumor TS genotype when loss of heterozygosity occurs in tumor DNA. A total of 30 colorectal cancer patients treated with the fluoropyrimidine-based combination S-1, all of whom had stage IV disease, were studied. The response rate to S-1 in this group of patients was 13 of 30 (43%). The heterozygous 2R/3R genotype was found in 22 of 30 normal tissues, whereas 10 (45%) of the matched cancer tissues showed only the 2R-sequence band (2R/loss), and 7 cancer tissues (32%) showed only the 3R-sequence band (3R/loss). The response rate of the 2R/loss tumor genotype patients was 80% (8 of 10) compared with 14% (1 of 7) in the 3R/loss genotype group (P = 0.029). Patients with tumor 3R/loss genotypes had significantly lower survival than 2R/loss genotypes. Heterozygous patients with a 2R/loss tumor genotype had the same survival as 2R/2R patients, whereas patients with a 2R/3R tumor genotype had a short survival similar to homozygous 3R/3R genotypes. These results show that: (a) response to 5-fluorouracil-based therapy is determined by tumor genotype; and (b) the 3R repeat is a direct negative determinant of outcome.