DNA甲基化与前列腺癌

DNA甲基化是恶性肿瘤普遍存在的分子生物学改变,与肿瘤的发生和发展密切相关。前列腺癌中存在多种基因的甲基化,涉及到DNA损伤修复、激素应答、肿瘤细胞入侵/转移、细胞周期调控等通路。前列腺癌前病变如前列腺上皮内瘤也存在DNA甲基化,但程度相对较低。DNA甲基化的研究为前列腺癌的早期诊断、预后评估及激素非依赖性前列腺癌的治疗提供了新的途径。     

DNA甲基化与前列腺癌

DNA甲基化是恶性肿瘤普遍存在的分子生物学改变，与肿瘤的发生和发展密切相关。前列腺癌中存在多种基因的甲基化，涉及到DNA损伤修复、激素应答、肿瘤细胞入侵／转移、细胞周期调控等通路。前列腺癌前病变如前列腺上皮内瘤也存在DNA甲基化，但程度相对较低。DNA甲基化的研究为前列腺癌的早期诊断、预后评估及激素非依赖性前列腺癌的治疗提供了新的途径。     

结直肠中ING1甲基化的性别不一致性研究

目的:检测结直肠癌中是否存在ING1启动子甲基化,ING1甲基化和性别的关系。方法:用甲基化特异性PCR方法检测62例结直肠癌患者的肿瘤组织、相应的正常黏膜的ING1的甲基化状况。结果:ING1甲基化在62份肿瘤标本中有26例发生了甲基化(41.9%),而在相应的正常组织中只有4例(6.45%)。DukesC、D期患者癌组织的甲基化发生率55.6%明显高于DukesA、B期(23.1%)。在肿瘤组织中ING1甲基化表现出明显的性别和年龄差异(P<0.05)。结论:结直肠癌中ING1的甲基化不仅和肿瘤的分期有关,而且可由年龄与性别相关的因素调节,可能是结直肠癌发生过程中的早期事件。     

Assessing the Use of p16 Promoter Gene Methylation in Serum for Detection of Bladder Cancer

Objective: This study was undertaken to investigate whether hypermethylation in p16^INK4a gene promoter could serve as plasma biomarker of bladder cancer.Methods and Patients: We examined the p16^INK4a status using methylation-specific PCR in 86 cancer patients and 49 controls (31 healthy people and 18 patients with benign urological diseases).Results: The p16^INK4a methylation was found in 22% of the serum samples and in 26% of the bladder cancer biopsies; one of them with carcinoma in situ. The presence of hypermethylated p16^INK4a in serum seems to be a product from tumour cells because a strong statistical association was found between both matched DNA signals (p<0.0001). Using the control group, the presence of methylated p16^INK4a in the serum of individuals with suspicion of bladder cancer was found to be associated with the tumour presence (p=0.0009). Aberrant p16^INK4a methylation was also observed in one non-cancer patient, which is undergoing further assessment.Conclusions: According with our results, methylation of p16^INK4a promoter may be involved in the bladder cancer genesis and the presence of p16^INK4a methylated in serum of these patients could be useful in the cancer diagnosis with values of sensitivity, specificity and positive predictive value of 0.226, 0.950 and 0.98, respectively. These figures support the use of methylated p16^INK4a as a new class of tumour marker in bladder cancer.     

p16基因甲基化在乳腺癌发展中的作用

目的 研究p16基因甲基化在乳腺癌中的分布情况,并探讨其与乳腺癌发生、发展的关系.方法 采用甲基化特异的PCR技术检测四川省肿瘤医院乳腺科2008年3～9月期间收治的38例原发性乳腺癌组织及距离肿瘤>5 cm以远的正常乳腺组织中p16基因启动子区CpG岛甲基化频率.结果 乳腺癌组织中p16基因启动子区CpG岛甲基化频率[31.6%(12/38)]明显高于其正常乳腺组织[5.3%(2/38)],差异有统计学意义(P=0.003).有淋巴结转移的乳腺癌患者中p16基因甲基化频率[45.5%(10/22)]高于无淋巴结转移患者[12.5%(2/16)],差异有统计学意义(P=0.044).结论 p16基因启动子区CpG岛甲基化可能在乳腺癌发生、发展过程中起着重要作用.     

Innovative Rapid Gene Methylation Analysis of Surgical Margin Tissues in Head and Neck Cancer

Background

Securing the negative surgical margin is the first step in surgical cancer treatment. However, tumor recurrence sometimes occurs even with histologically negative surgical margins. To detect minimal residual cancer cells in the deep margin intraoperatively, a time-efficient molecular approach is required.

Methods

We established an innovative rapid quantitative methylation PCR (QMSP) assay, which consists of substantially time-minimized DNA extraction, bisulfite treatment, and QMSP assays. To demonstrate the feasibility of this procedure, 10 serial surgical specimens of primary head and neck squamous cell carcinoma (HNSCC) were evaluated by both rapid and conventional QMSP. Two frequently methylated genes in head and neck cancer, homeobox A9 (HOXA9) and endothelin receptor type B (EDNRB) were analyzed in 10 HNSCCs and surgical margin tissues, as well as normal muscle and oral mucosa samples.

Results

The product quality of DNA extraction and bisulfite treatment using the time-saving procedure was comparable to the conventional procedure. In the QMSP assay, target gene methylation and reference gene methylation were equally detected by both the rapid and conventional method. Finally, relative results of rapid and conventional QMSP were quite similar to each other in tumors, margins, and normal tissues. The average total time required for the rapid QMSP procedure was less than 3 h and could be accomplished by a single person.

Conclusion

From the viewpoint of accuracy, cost, and time consumption, the innovative rapid QMSP maintains highly sensitive methylation detection accomplished within the time frame of a major ablative and reconstructive procedure.     

miR-34b基因启动子区甲基化与甲状腺乳头状癌的关系

目的探讨甲状腺乳头状癌（PTC）中微小RNA-34b（miR-34b）基因的表达及其启动子区的甲基化情况,并分析甲基化与其临床病理特征的关系。方法收集2008年9月至2010年10月期间南京医科大学附属淮安第一医院行手术切除的25例PTC患者的癌组织和癌旁组织。采用实时定量PCR法检测其miR-34b mRNA的表达,采用甲基化特异性（MSP）PCR法检测miR-34b基因启动子区的甲基化情况。结果 PTC癌组织中miR-34bmRNA的相对表达量为0.85±0.05,较癌旁组织的1.62±0.09低（P=0.030）。25例PTC癌组织中,有18例（72%）患者的miR-34b基因启动子区发生甲基化,癌旁组织组有10例（40%）,癌组织的甲基化比例较高（P=0.021）。甲基化与PTC患者的年龄、性别、肿瘤大小、TNM分期和包膜浸润均无关（P〉0.05）,而与淋巴结转移有关,发生淋巴结转移者的甲基化比例高于未发生淋巴结转移者（P〈0.05）。结论 PTC癌组织中miR-34b基因启动子区的异常甲基化可能是该基因失活的原因之一,并且可能与PTC的发生、发展以及转移均有关,其机理值得进一步研究。     

膀胱移行细胞癌中FHIT基因启动子甲基化及其蛋白的表达

目的：探讨膀胱移行细胞癌（BTCC）FHIT基因启动子甲基化状态及其与FHIT蛋白表达的关系。方法：采用甲基化特异性PCR（MSPCR）方法及免疫组织化学S-P法检测62例BTCC组织和10例正常膀胱组织中FHIT基因启动子甲基化状态及FHIT蛋白表达。结果：BTCC组织、正常膀胱组织FHIT基因启动子甲基化频率分别为19．4％（12／62）,0（0／10）。FHIT蛋白在正常膀胱组织、BTCC中阳性表达率分别为100．0％（10／10）和46．77％（29／62）,肿瘤不同分级中随恶性程度的增高,表达减少,Ⅰ级与Ⅲ级比较,差异有统计学意义（P〈0．05）,不同临床分期中随分期的增高,表达减少,Tis～T1与T2～T1比较,差异无统计学意义（P〉0．05）。FHIT基因的启动子甲基化和蛋白阳性表达有相关（P〈0．05）。结论：FHIT基因的启动子甲基化可能是基因失活重要机制之一,FHIT基因启动子甲基化及表达在BTCC的发生、发展中起重要作用。     

肿瘤抑制基因甲基化与胃癌

目的 探讨肿瘤抑制基因甲基化与胃癌的关系。方法 对近年来关于肿瘤抑制基因甲基化与胃癌关系的文献进行综述分析。结果 胃癌中，细胞周期调控基因、有丝分裂检测点基因、凋亡相关基因、错配修复基因、转移相关基因等多种肿瘤抑制基因发生甲基化而失活。结论 肿瘤抑制基因甲基化在胃癌的发生、发展过程中起重要作用，肿瘤抑制基因的甲基化有可能成为胃癌诊断、判断转移和评价预后的分子标记物，去甲基化干预有望成为胃癌治疗的新方法。     

肿瘤坏死因子相关凋亡诱导配体启动子区-716位点单核苷酸多态性与前列腺癌危险因素的研究

目的：研究肿瘤坏死因子相关凋亡诱导配体（TRAIL）启动子区-716A／G位点单核苷酸多态性（SNP）与影响前列腺癌危险因素的关系。方法：应用聚合酶链反应-连接酶特异检测技术（PCR-LDR）分析186例前列腺癌患者TRAIL基因-716位点的多态性,比较不同基因型与前列腺癌患者诊断时的前列腺癌特异性抗原（PSA）、Gleason评分和TNM临床分期的关系。结果：TRAIL-716G（AG＋GG）等位基因与PSA、Gleason评分和TNM临床分期均具有显著的相关性（adjustedOR=0．04,0．07,0．08;95％CI：0．01～0．14,0．02～0．29,0．03～0．21）。结论：TRAIL-A716G（AG＋GG）等位基因可能与前列腺癌预后有关,携带TRAIL-716G（AG＋GG）等位基因的前列腺癌患者可能预后较好。     

凋亡抑制基因XIAP在前列腺癌细胞中的表达及与临床病理特征的关系

目的 :研究XIAP基因在前列腺癌细胞系和前列腺癌组织的表达情况 ,及其与前列腺癌临床病理特征的关系。　方法 :应用RT PCR检测前列腺癌组织、正常前列腺组织和前列腺癌细胞株PC 3,DU 14 5 ,LNCaP细胞XIAP基因的表达 ,并通过免疫组化SP法检测 5 6例前列腺癌组织标本XIAP蛋白的表达情况。　结果 :XIAP基因在前列腺癌组织和前列腺癌细胞株PC 3,DU 14 5 ,LNCaP细胞高表达 ,正常前列腺组织无表达。在前列腺癌组织和癌旁组织中 ,XIAP蛋白阳性检出率分别为 5 3.6 % (30 / 5 6 )和 2 1.5 % (12 / 5 6 ) (P <0 .0 1) ;不同分期、分级组XIAP阳性检出率相比差异无显著性 (P >0 .0 5 )。　结论 :凋亡抑制基因XIAP与前列腺癌相关 ,在前列腺癌发生过程中具有重要的作用 ,有可能成为前列腺癌治疗的靶标。     

Kallikrein 10基因在前列腺癌组织中的表达及意义

目的：探讨Kallikrein10（KLK10）基因在不同前列腺组织中的表达情况。方法：采用荧光定量PCR方法检测3例正常前列腺组织、5例BPH组织、6例前列腺癌细胞株、35例前列腺癌组织中KLK10mRNA的表达水平。结果：正常前列腺组织、良性前列腺增生组织、前列腺癌细胞株、前列腺癌组织KLK10 mRNA表达相对值分别为0．521、0．487、0．021、0．018,组间比较差异有统计学意义（P〈0．01）。骨转移前列腺癌与未转移前列腺癌KLKIOmRNA表达相对值分别为0．003、0．023,两组比较差异有统计学意义（P〈0．05）。结论：KLK10在前列腺癌组织中表达下调,在转移性前列腺癌中表达更低。KLK10表达下调可促进肿瘤的发生与进展。     

Death-Associated Protein Kinase (DAPK) Promoter Methylation and Response to Neoadjuvant Radiochemotherapy in Esophageal Cancer

Background  Multiple studies have shown that promoter methylation of tumor suppressor genes underlies esophageal carcinogenesis. Hypothetically, methylation resulting in tumor suppressor gene inactivation might result in tumors that are unresponsive to chemotherapy and radiation. Accordingly, our aim was to investigate if aberrant methylation of the apoptosis-related gene Death-Associated Protein Kinase (DAPK) could be used as a predictor of response to neoadjuvant therapy in locally advanced cancer of the esophagus. Methods  Tumor and normal esophageal tissues were obtained from 50 patients with locally advanced cancer of the esophagus prior to neoadjuvant radiochemotherapy. DAPK methylation analysis was performed on all samples by methylation-specific real-time polymerase chain reaction (PCR). Results  Seventeen (34%) patients showed a major and 33 (66%) a minor histomorphological response to neoadjuvant therapy. DAPK methylation was detectable in normal esophageal tissues with a frequency of 10% and in tumor tissue with a frequency of 78%. The median methylation level for DAPK was 2.7 × 10⁻³ in tumor compared with 0.1 × 10⁻³ in normal tissues (p < 0.001). DAPK methylation was not associated with response to neoadjuvant therapy or prognosis after esophagectomy. Conclusion  Aberrant DAPK methylation in tumor tissues is significantly higher compared with matching normal esophageal tissues, suggesting a fundamental role of this epigenetic alteration in the pathogenesis of this disease. The level of DAPK methylation in pretreatment biopsies of patients with locally advanced cancer of the esophagus is no marker for the prediction of histomorphological regression or prognosis following neoadjuvant chemoradiation in this disease.