Polymorphism of thymidylate synthase gene associated with its protein expression in human colon cancer

AIM： To correlate the polymorphisms in the 5＇-untranslated region with thymidylate synthase （TS） protein expression in Han Chinese colonic neoplasms. METHODS： Adenocarcinoma samples were from 68 patients who received no treatment before surgery. Tandem repeat length of TS gene was determined by PCR amplification of genomic DNA. Intratumoral TS protein expression was studied immunohistochemically in corresponding sections from paraffin-embedded primary loci. Immunoreactivity was semiquantitatively evaluated by immunoreactivity score （IRS）. RESULTS： Double-（2R） and triple-repeated （3R） sequences of the TS gene were found in the cancer tissues. Three genotypes of TS were found： 2R/2R （n = 6）, 2R/3R （n = 22） and 3R/3R （n = 40）. Patients who were homozygous for triple-repeated （3R/3R） sequences showed significantly higher IRS of TS than patients who were homozygous for double-repeated （2R/2R） sequences or heterozygous patients （2R/3R）： 5.73 ±3.25 vs 2.17 ± 1.47 or 3.77 ±2.64, P = 0.008 or P = 0.015. But no statistical significance of IRS in cancer tissues was observed between 2R/3R genotype and 2R/2R genotype. CONCLUSION： There is a relationship between TS genotype and TS protein expression in clinical specimens. The data might offer an advantage for selection of Chinese cancer patients to receive fluoropyrimidines treatment.

Expression of thymidylate synthase and glutathione-stransferase π in patients with esophageal squamous cell carcinoma

AIM： To investigate the expression of thymidylate synthase （TS） and glutathione-s-transferase π （GST-π） in esophageal squamous cell carcinoma and their association with the clinicopathologic characteristics. METHODS： Immunohistochemical methods were used to detect the expression of TS and GST-π in surgically resected formalin-fixed, paraffin-embedded esophageal squamous cell carcinoma （ESCC） tissue sections from 102 patients （median age, 58 years） and in 28 normal esophageal mucosa （NEM） samples. The relationship between TS and GST-π expression and clinicopathologic factors was examined. RESULTS： The expression of TS and GST-π was not statistically significantly associated with age of the patients, tumor size, lymph node metastasis, depth of invasion or tumor stage. TS staining was positive in 17.86% of normal esophageal mucosa and in 42.16% of ESCC samples （P 〈 0.05）. The expression level of TS was not only significantly lower in well-differentiated （21.88%） than in poorly-differentiated carcinomas （51.43%, P 〈 0.05）, but was also significantly higher in samples from male patients （46.51%） than from female patients （18.75%, P 〈 0.05）. GST-π was positively stained in 78.57% of normal esophageal mucosa and in 53.92% of ESCC samples （P 〈 0.05）. The expression level of GST-π was also significantly higher in welldifferentiated carcinomas （65.63%） than in poorly- differentiated carcinomas （35.00%, P 〈 0.05）. CONCLUSION： The expression of TS and of GST-π may be used as molecular markers for the characterization of ESCC. Poorly-differentiated cells showed increased expression of T5 and reduced expression of GST-π.

Immunohistochemical expression of thymidylate synthase and prognosis in gastric cancer patients submitted to fluoropyrimidine-based chemotherapy

Objective： Adjuvant chemotherapy with 5-fluorouracil （5-FU） has been widely used in gastric cancer （GC） patients to prevent relapse after curative resection. 5-FU acts by inhibiting thymidylate synthase （TS）, and high levels of TS correlate with resistance to treatment with fluoropyfimidines. The aim of this study was to evaluate the expression of TS in GC patients, and its relation with clinicopathological characteristics and prognosis in adjuvant chemotherapy with 5-FU. Methods： We retrospectively evaluated 285 patients who underwent D2-gastrectomy with curative intent. TS expression was determined by immunohistochemistry （IHC） in tumor cells by tissue microarray （TMA）. TS level was evaluated according to the intensity and percentage of cells marked by a score system. Patients were divided in three groups according to their TS-score： negative, low and high. Results： TS expression was positive in 92.3% of GC. TS-high, TS-low and TS-negative were observed in 46.3%, 46.0% and 7.7% of patients, respectively. High-TS GC were associated with older age （P=0.007）, high neutrophil/lymphocyte ratio （P=0.048）, well/moderately differentiated histology （P=0.001）, intestinal Lauren type （P〈0.001） and absence of perineural invasion （P=0.003）. Among 285 patients, 133 stage IUIII patients （46.7%） received chemotherapy with 5-FU. In survival analysis, TS-high was associated with worse disease-free survival （DFS） in stage III GC patients who received 5-FU-based chemotherapy （P=0.007）. Multivariate analysis revealed that total gastrectomy, poorly differentiated tumors and high TS-score were associated with worse DFS in stage III GC patients. Conclusions： High TS-score in stage III GC was associated with poor DFS in patients treated with fluoropyrimidine-based chemotherapy.

Bcl-2 expression significantly correlates with thymidylate synthase expression in colorectal cancer patients

AIM: To examine the expression of thymidylate synthase (TS) and oncoprotein Bcl-2 in advanced colorectal cancer (CRC) patients,and to determine their mutual relationship,association to therapeutic response and impact on disease outcome.METHODS: Tumor samples from 67 patients with CRC,who were treated at advanced stage with either irinotecan alone or in combination with 5-fluorouracil/ leucovorin,were analyzed for expression of TS and Bcl-2 using immunohistochemistry.RESULTS: A significant linear correlation between lower expression levels of Bcl-2 and lower levels of TS expression was found (P = 0.033).Patients with high levels of both TS and Bcl-2 expression had a significantly longer disease-free survival (DFS) (42.6 mo vs 5.4 mo,n = 25) than those with low TS/Bcl-2 index (P = 0.001).Tumors with low levels of both TS and Bcl-2 were associated with a longer survival with metastasis (WMS) interval in the whole patients group (n = 67,P = 0.035).TS/Bcl-2 index was not significantly related to disease-specific survival.CONCLUSION: The present data suggest that CRC patients with low TS/Bcl-2 demonstrate a significantly shorter DFS and longer WMS.

Predictive value of Ki67 and p53 in locally advanced rectal cancer:Correlation with thymidylate synthase and histopathological tumor regression after neoadjuvant 5-FU-based chemoradiotherapy

AIM: To investigate the predictive value of Ki67 and p53 and their correlation with thymidylate synthase (TS) gene expression in a rectal cancer patient cohort treated according to a standardized recommended neoadjuvant treatment regimen.METHODS: Formalin fixed, paraffin embedded pre-therapeutical tumor biopsies (n = 22) and post-therapeutical resection specimens (n = 40) from patients with rectal adenocarcinoma (clinical UICC stage Ⅱ/Ⅲ) receiving standardized neoadjuvant 5-fluorouracil (5-FU) based chemoradiotherapy were studied for Ki67 and p53 expression by immunohistochemistry and correlated with TS mRNA expression by quantitative TaqMan real-time PCR after laser microdissection. The results were compared with histopathological tumor regression according to a standardized semiquantitative score grading system.RESULTS: Responders (patients with high tumor regression) showed a significantly lower Ki67 expression than non-responders in the pre-therapeutical tumor biopsies (81.2% vs 16.7%; P < 0.05) as well as in the post-therapeutical resection specimens (75.8% vs 14.3%; P < 0.01). High TS mRNA expression was significantly correlated with a high Ki67 index and low TS mRNA expression was significantly correlated with a low Ki67 index in the pre-therapeutical tumor biopsies (corr. coef. = 0.46; P < 0.01) as well as in the post-therapeutical resection specimens (corr. coef. = 0.40; P < 0.05). No significant association was found between p53 and TS mRNA expression or tumor regression.CONCLUSION: Ki67 has, like TS, predictive value in rectal cancer patients after neoadjuvant 5-FU based chemoradiotherapy. The close correlation between Ki67 and TS indicates that TS is involved in active cell cycle processes.

Thymidylate synthase and thymidine phosphorylase gene expression as predictive parameters for the efficacy of 5-fluorouraci-based adjuvant chemotherapy for gastric cancer

AIM： To investigate the prognostic role of thymidylate synthase （TS） and thymidine phosphorylase （TP） mRNA levels in T3 or T4 gastric cancer treated with 5-fluorouraci-based adjuvant chemotherapy. METHODS： Fifty-one patients with T3 or T4 gastric cancer received systemic 5-fluorouraci-based adjuvant chemotherapy, and intratumoral expression of TS and TP in 51 gastric cancer tissue samples was tested by realtime quantitative PCR.RESULTS： The median disease-free survival （DFS） time was 10.2 mo in the patients. There were no significant differences in DFS between the groups with high and low levels of TP. However, the group with low level of TS had a longer DFS （14.4 mo vs 8.3 mo, P = 0.017）. The median overall survival （OS） time was 18.5 mo, and there were significant differences in OS between the groups with high and low levels of TS or TP （for TS, 17.0 mo vs 21.3 mo, P = 0.010; for TP, 16.6 mo vs 22.5 too, P = 0.009）. Moreover, the coupled low expression of these two genes was strongly associated with a longer survival time of patients as compared with that of a single gene.CONCLUSION： Expression of TS and TP mRNA is a useful predictive parameter for the survival of postoperative gastric cancer patients after 5-fluorouracilbased adjuvant chemotherapy.

Structural analysis of a shrimp thymidylate synthase reveals species-specific interactions with dUMP and raltitrexed

Thymidylate synthase(TS)is a key enzyme in the de novo biosynthesis of thymidine monophosphate,serving as a well-known drug target in chemotherapy against cancers and infectious diseases.Additional to its clinical value,TS is supposed to be a promising drug target in aquatic-disease control.To facilitate designing pathogen-specific TS inhibitors for shrimp-disease control,we report the crystal structures of TS from Litopenaeus vannamei(LvTS)in the apo form,LvTS-dUMP complex and LvTS-dUMP-raltitrexed complex at 2.27Å,1.54Å,and 1.56Åresolution,respectively.LvTS shares a similar fold with known TSs,existing as a dimer in the crystal.The apo LvTS and LvTS-dUMP take an open conformation,and raltitrexed binding induces structural changes into a closed conformation in LvTS-dUMP-raltitrexed.Compared to those in other known TS-dUMP-raltitrexed complexes with the closed conformation,the C-terminal loop in LvTS-dUMP-raltitrexed shifts its position away from the bound raltitrexed;the distance between C6 of dUMP and Sγof the catalytic cysteine is obviously longer than that in the known TS structures with closed conformations,resembling that in the TS structures with open conformations.Other species-specific interactions with dUMP and raltitrexed are also observed.Therefore,LvTS-dUMP-raltitrexed adopts a loosely closed conformation with structural features intermediate between the closed and the open conformations that were reported in other TSs.Our study provides the first crustcean TS structure,and reveals species-specific interactions between TSs and the ligands,which would facilitate designing pathogen-specific TS inhibitors for shrimp-disease control.

Relationship between the Expression of Thymidylate Synthase,Thymidine Phosphorylase and Dihydropyrimidine Dehydrogenase and Survival in Epithelial Ovarian Cancer

The mRNA and protein expression of thymidylate synthase (TS), thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) and their relationship with prognosis were investigated. Real-time quantitative RT-PCR (Taqman) was used to detect the mRNA expression of TS, TP and DPD in formalin-fixed and paraffin-embedded 106 samples of epithelial ovarian cancer and 29 normal ovaries. A TATA box-binding protein (TBP) was used as an endogenous reference gene. A relationship between TS, TP, DPD expression and clinicopathologic features was investigated. The protein location and expression of TS, TP and DPD was examined in the same patients by an avidin-biotin-peroxidase immunohistochemistry. TS and TP mRNA expression levels were significantly higher in tumor group than in normal controls, with the average value of TS and TP mRNA being 6.14±0.62 and 0.59±0.06 in tumor tissue, and 0.71±0.14 and 0.16±0.04 in normal tissue, respectively. DPD mRNA expression levels were significantly lower in tumor group (0.11±0.02) than in normal controls (0.38±0.05). There was statistically significant difference in TS and TP mRNA expression levels among different pathological grades and clinical stages (P<0.05), but histological subtype was not significantly associated with TS and TP mRNA expression. DPD gene expression was not significantly associated with any clinicopathological parameters. Immunohistochemistry revealed that TP protein was mainly distributed in nucleus, and TS and DPD mainly in cytoplasm. The protein expression intensity of TS, TP and DPD was coincided with the mRNA expression levels. It was concluded that TS, TP mRNA and protein expression levels were significantly higher in epithelial ovarian cancer, and DPD mRNA and protein expression levels were significantly lower. The expression levels of TS and DPD were related to the patients’ prognosis and survival. Combined gene expression levels of TS, TP and DPD represent a new variable to predict the clinical outcome in ovarian cancer. The association of TS, TP and DPD expression levels with survival suggests an importance of these genes for tumor occurrence and progression.

Herbal formula enhances 5-fluorouracil activity through suppression of thymidylate synthase

Traditional Chinese herbal medicine(TCM)has been shown to enhance the efficacy of standard anticancer agents.However,there are only a limited number of well-controlled preclinical and clinical studies documenting the potential benefit of TCM.OBJECTIVE To identify biologically active formulas that were effective against colorectal cancer(CRC)by screening TCM formulas in in vitro and in vivo animal models.METHODS Cell growth assays,cell cycle analysis,immunoblot analysis and qRT-PCR were performed to investigate the mechanism(s)of action of the formulason human CRC cells.In vivo animal models were used to evaluate the antitumor activity of formulasalone and in combination with 5-FU.RESULTS We identified Huangqin Gegen Tang(HQGGT)which suppressed the in vivo growth of human CRC HT-29 xenografts.HQGGT significantly inhibited the growth of CRC cell lines.HQGGT enhanced the cytotoxicity of 5-FU against human 5-FU-resistant cells(H630R1)and mouse colon cancer cells(MC38).This synergy was the result of suppression of thymidylate synthase expression by HQGGT.HQGGT significantly enhanced the antitumor effect of 5-FU in mice bearing MC38 xenografts.Ongoing studies have identified Huangqin as the herb responsible for TS inhibi⁃tion.CONCLUSION These findings provide support for the potential role of HQGGT as a novel modulator of fluoropyrim⁃idine chemotherapy for CRC treatment.

The Role of Thymidylate Synthase in Pemetrexed-Resistant Malignant Pleural Mesothelioma Cells

We established new pemetrexed-resistant cells originating from malignant pleural mesothelioma MSTO-211H cells to clarify the mechanism involved in pemetrexed resistance in malignant pleural mesothelioma. In the pemetrexed-resistant cells, only thymidylate synthase (TYMS) mRNA was overexpressed among other well-known molecular targets and chemosensitivity determinants of pemetrexed, and the role of the TYMS gene was ascertained by artificial regulation induced by specific siRNA. Silencing the TYMS expression partially restored the cytotoxicity of pemetrexed. The resistant cells did not display other gene alterations related to folate metabolism. We conclude that the primary mechanism imparting resistance to these cells is specific up-regulation of TYMS function. Further, the TYMS gene may serve as a useful biomarker for the prediction of pemetrexed chemosensitivity in patients with malignant pleural mesothelioma. We also investigated the efficacy of 1-(3-C-ethynyl-β-D-ribo-pento furanosyl)cytosine (ECyd) in overcoming pemetrexed resistance;this compound is presently undergoing clinical trials in the USA as TAS-106. ECyd had a similar antitumor effect on the resistant cells as that on the parental cells. In the clinical treatment of malignant pleural mesothelioma, ECyd promises to emerge as a novel drug.

Thymidylate synthase confers pemetrexed resistance of non-small cell lung cancer cells by EGFR/PI3K/AKT pathway

Chemotherapy drug resistance is the main cause leading to the relapse and metastasis of non-small cell lung cancer(NSCLC)patients.Our study aimed to investigate the mechanism of pemetrexed resistance in NSCLC.Firstly,the pemetrexed(PEM)-resistant PC-9 and A549 lung adenocarcinoma cell lines(PC-9/PEM and A549/PEM)were established.The expression of thymidylate synthase(TS)in PC-9/PEM,A549/PEM,A549,and PC-9 cells were analyzed by qRT-PCR and western blot.Then,cell viability,colony formation,migration,and invasion were performed on PEM-resistant cells transfected with TS siRNA.The role of EGFR in PEM resistance of PEM-resistant cells was investigated using EGFR siRNA.The effects of gefitinib and EGFR siRNA on EGFR/PI3K/AKT pathway and downstream signaling Cyclin D1 and E2F1 in PEM-resistant cells were analyzed.Results showed that the protein level of TS was significantly increased in A549/PEM and PC-9/PEM.TS knockdown inhibited the potency of proliferation,colony-forming potential,migration,and invasion in PEM-resistant cells.EGFR knockdown abrogated the resistance to PEM of PEM-resistant cells and suppressed the migration and invasion of PEM-resistant cells.Gefitinib treatment and EGFR knockdown respectively inhibited the EGFR/PI3K/AKT pathway and downregulated Cyclin D1 and E2F1 in PEM-resistant cells.Thus,TS might be a predictive marker for PEM resistance in NSCLC.Inhibition of the EGFR pathway abrogated the resistance to PEM and inhibited the EGFR/PI3K/AKT and downstream signaling of PEM-resistant NSCLC cell lines.

Good Response to Pemetrexed after Treatment Failure with Another Thymidylate Synthase Inhibitor in Lung Adenocarcinoma: A Case Report

Pemetrexed is an antimetabolic agent and is well-known as a potent inhibitor of thymidylate synthase (TS). It also inhibits dihydrofolate reductase (DHFR) and glycinamide ribonucleotide formyl transferase (GARFT). We reported an intriguing case in which a non-small cell lung cancer patient who was refractory to pretreatment with S-1, a strong TS inhibitor, showed good response to pemetrexed treatment.

Correlation between Thymidylate Synthase Genotype and Susceptibility to Gastric Carcinoma

OBJECTIVE To investigate the correlation between polymorphism of the 5′-untranslated region （5′-UTR） of thymidylate synthase genes, as well as the lifestyle, and the susceptibility of gastric carcinoma. METHODS A case-control study, with 60 cases of gastric carcinoma and 170 cases of general risk population-based controls from Nantong, Jiangsu province, China, was conducted. The epidemiological data, such as living habits of the cancer patients, were collected. DNA of peripheral blood leukocytes was obtained from all of the subjects. The TS 5′-UTR tandem repeat genotype was detected using polymerase chain reaction （PCR）. RESULTS There were three TS 5′-UTR genotypes in the group of gastric cancer cases （2R/2R, 2R/3R and 3R/3R） and six TS 5′-UTR genotypes in the group of the controls （2R/2R, 2R/3R, 3W3R, 2R/4R, 2R/5R and 3R/4R）. The genotypic frequencies were respectively 5.0%, 43.3% and 51.7% in the gastric cancer group. Compared with the parameters in the control group, i.e., 4.7%, 31.7%, 60.6%, 1.2%, 1.2% and 0.6%. There were no significant differences between the two groups. Compared with the 3R/3R- genotype individuals who where non-smokers, drank alcohol twice or less each week, drank tea and did not intake pickled food （PF）, the risk of gastric cancer significantly went up in the 2R/2R or 2R/3R-genotype people who had habits of smoking, drinking alcohol more than twice each week, no tea drinking but with frequent intake of PF. The adjusted ORs were as follows, 3.79 （95% CI： 2.45-8.64）, 3.41 （95% CI and 3.61 （95% CI： 1.81-8.78）. CONCLUSION There is 1.21-8.47）, 5.99 （95% Ch 3.01-14.7）, an obvious correlation between the polymorphisms of TS 5′-UTR genotypes and the lifestyle of individuals in the development of gastric carcinoma.

TS mRNA水平对食管癌化疗的预测价值

目的探讨化疗前食管癌组织中胸苷酸合成酶(thymidylate synthase,TS)转录水平及其对顺铂/5-氟脲嘧啶(DDP/5-Fu)疗效的预测价值.方法 20例食管癌患者均接受2个周期DDP/5-Fu化疗.DDP 15～20 mg/m2/d,iv d1-5;5-Fu 375～500 mg/m2/d,ivgtt 8 h,d1-5,休息4周后,进行第二个周期化疗.以β-肌动蛋白(β-actin)作内参照,应用半定量RT-PCR技术检测化疗前食管癌癌组织中TS mRNA水平,以TS/Β-actin比值表示.实验数据经SPSS 10.0统计软件处理,化疗有效和无效组间TS mRNA水平间差异分析采用Wilcoxon秩和检验;双侧检验,α取0.05作为显著性检验的标准.结果 20例食管癌患者中,11例化疗有效者的TS/β-actin mRNA水平中位值为3.90×10-1,而9例化疗无效者的TS/β-actin mRNA水平中位值为9.10×10-1,两组差异具有统计学意义(P<0.05).结论化疗前食管癌组织中TS mRNA水平对应用DDP/5-Fu治疗食管癌的疗效具有一定预测价值.

TS基因表达与培美曲塞治疗老年晚期肺腺癌疗效关系的研究

目的探讨老年晚期肺腺癌患者胸苷酸合成酶(TS)基因与培美曲塞疗效的关系。方法收集37例老年晚期肺腺癌患者,随机分为培美曲塞联合卡铂方案组和紫杉醇联合卡铂方案组;RT-PCR检测肿瘤组织中TS mRNA的表达,Western blotting检测TS蛋白的表达。结果两组疾病控制率差异无统计学意义。TS mRNA和蛋白的表达与年龄、性别及分期无关。培美曲塞联合卡铂组中获疾病控制者(CR+PR+SD)的TS mRNA和蛋白表达量为5.08±2.30和4.46±2.22,进展者(PD)为13.66±3.84和12.6±3.92,差异均有统计学意义(P<0.05)。紫杉醇联合卡铂方案组中获疾病控制者与进展者的TS mRNA和蛋白表达差异均无统计学意义(P>0.05)。结论肺腺癌患者肿瘤组织中TS基因的表达与患者对培美曲塞的敏感性相关,TS基因高表达提示对培美曲塞敏感性降低。

叶酸、蛋氨酸摄入量,MTR、TS基因多态与结直肠癌关系的巢式病例对照研究

目的:研究蛋氨酸合酶(methioninesynthase,MTR)、胸苷酸合酶(thymidylatesynthase,TS)基因多态性,叶酸、蛋氨酸摄入量与结直肠癌易感性的关系。方法:采用巢式病例对照研究设计(病例140例和对照343例),通过非条件Logistic回归模型分析各多态与结直肠癌易感性的关系,及其与叶酸、蛋氨酸摄入量之间的联合作用。结果:MTR2756G等位基因携带者患结直肠癌的风险显著增高(OR=2.04,95%CI,1.22～3.39)。TS5’-UTR多态与叶酸摄入量之间的联合作用与结直肠易感性的关系有统计学意义(P=0.01)。结论:MTR2756G等位基因是结直肠癌的危险因素,TS5’-UTR多态与叶酸摄入量之间可能存在交互作用。

HK-Ⅱ、TS和Ki-67在青年人结肠癌组织中的表达及其意义

目的检测己糖激酶-Ⅱ(HK-Ⅱ)、胸苷酸合成酶(TS)和Ki-67核抗原(Ki-67)在青年人结肠癌组织中的表达,并探讨其临床意义。方法采用免疫组织化学法检测78例青年人(≤40岁)结肠癌和75例随机抽取的同期收治的中老年人(>40岁)结肠癌组织中HK-Ⅱ、TS及Ki-67蛋白的表达。结果 HK-Ⅱ和TS在青年人组和中老年人组结肠癌组织中的阳性表达率分别为82.1%(64/78)和65.3%(49/75),69.2%(54/78)和52.0%(39/75),而Ki-67增殖指数分别为(59.1±3.0)%和(48.5±3.2)%。两组比较,以上三种蛋白的表达水平差异均有统计学意义(均P<0.01)。HK-Ⅱ、TS及Ki-67表达在青年人结肠癌肿瘤分化程度、分期之间的差异均有统计学意义(均P<0.05)。青年人结肠癌HK-Ⅱ表达与TS、Ki-67成正相关性。结论 HK-Ⅱ、TS和Ki-67阳性蛋白表达可作为青年人结肠癌的恶性指标。

二氢嘧啶脱氢酶(DPD)与胸苷酸合成酶(TS)在结直肠癌中的表达及预后价值

目的:探讨5-FU代谢酶在结直肠癌中的表达及其与预后的关系。方法:44例结直肠癌根治术后分别施以5-FU为主的辅助化疗,并通过免疫组化检测二氢嘧啶脱氢酶(DPD)和胸苷酸合成酶(TS)的表达。结果:DPD阳性表达的结直肠癌无病生存期显著缩短(P=0.047),而总生存期也有缩短的趋势,但差异无显著意义(P=0.136)。而TS表达与预后无关(P>0.05),但TS在晚期肿瘤中表达较高(P<0.05)。结论:在接受5-FU为主辅助化疗的结直肠癌患者中,DPD表达可作为预后的重要指标。TS表达与临床分期密切相关,可视为结直肠癌进展的生物学标志。

TS、p53基因产物表达水平与直肠癌预后的关系

目的 :探讨TS基因和 p5 3基因产物表达与直肠癌术后复发转移和预后的关系。 方法 :采用免疫组织化学方法对 4 2例直肠癌手术标本中的TS基因和 p5 3基因产物进行检测和分析。 结果 :TS基因产物的高表达率为 4 5 5 % (2 0 / 4 2 ) ,p5 3基因产物的高表达率为 4 3 2 % (19/ 4 2 )。TS基因产物低表达患者的局部复发率和远处转移率明显低于高表达患者 (P =0 0 14 ,0 0 0 5 ) ,无病生存期明显长于高表达患者 (P =0 0 0 0 6 )。在 2 4例术后辅助化疗患者中 ,TS基因产物低表达患者的局部复发率和远处转移率均明显低于高表达患者 (P =0 0 0 7,0 0 0 5 )。p5 3基因产物高表达与局部复发、远处转移以及无病生存期之间未见明显的相关性。多因素分析结果显示TS基因产物表达是影响直肠癌患者术后无病生存期的独立因素。结论