上皮性卵巢肿瘤RASSF1A基因甲基化与蛋白表达的关系及意义

目的：检测上皮性卵巢肿瘤中RASSF1A基因启动子CpG岛的甲基化状态,并探讨基因异常甲基化与蛋白表达的关系及其意义。方法：运用甲基化特异性PCR（MSP）方法对62例上皮性卵巢癌、21例交界性囊腺瘤及30例良性囊腺瘤的RASSF1A基因启动子甲基化状态进行检测,免疫组化S-P法检测上述标本中RASSF1A蛋白表达,并结合肿瘤生物学行为进行分析。结果：上皮性卵巢癌组织、卵巢交界性囊腺瘤组织中RASSF1A基因启动子区甲基化率（58.06%、42.85%）显著高于卵巢良性囊腺瘤组织（13.33%）,差异有统计学意义（P〈0.05）。RASSF1A基因启动子区甲基化与上皮性卵巢癌的细胞分化程度和临床分期密切相关（P〈0.05）而与组织类型和患者年龄及绝经与否无相关性（P〉0.05）;RASSF1A基因甲基化与其蛋白表达下降一致。结论：卵巢癌组织中存在RASSF1A基因启动子CpG岛的异常甲基化,可能和该蛋白表达缺失的主要原因,是导致该基因失活的重要机制之一。     

上皮性卵巢癌组织中WWOX基因启动子区域CpG岛的甲基化状态及临床意义

目的研究上皮性卵巢癌组织中WWOX基因启动子区CpG岛的甲基化状态,并分析WWOX基因的甲基化与上皮性卵巢癌的临床病理指标之间的关系。方法采用甲基化特异性PCR(methylation specific polymerase chain reaction,MSP)方法检测48例上皮性卵巢癌、18例卵巢交界性上皮性肿瘤、26例卵巢良性上皮性肿瘤及33例正常卵巢组织中WWOX基因CpG岛甲基化状态。结果上皮性卵巢癌、卵巢交界性上皮性肿瘤、卵巢良性上皮性肿瘤组织中WWOX基因启动子区CpG岛甲基化率分别为43.75%、26.32%、3.84%,正常卵巢组织中未检测到WWOX基因CpG岛甲基化。上皮性卵巢癌组织中WWOX基因CpG岛的甲基化率明显高于其他卵巢组织,差异有统计学意义(P<0.01)。晚期(Ⅲ期、Ⅳ期)上皮性卵巢癌组织中WWOX基因CpG岛的甲基化率高于早期(Ⅰ期、Ⅱ期)上皮性卵巢癌组织,差异有统计学意义(P<0.05)。结论 上皮性卵巢癌组织中广泛存在着WWOX基因启动子区CpG岛甲基化,可能是导致WWOX基因失活的重要机制。WWOX基因的异常甲基化可能与上皮性卵巢癌的发生发展密切相关,其可能成为上皮性卵巢癌的早期诊断和评估预后的重要指标。     

Kilon基因在卵巢上皮性肿瘤中的表达状况的探讨

目的 探讨Kilon基因在卵巢上皮性癌中的表达状态及其与基因启动子CpG岛甲基化的关系。方法 采用RTPCR的方法检测20例卵巢正常组织，17例良性上皮性肿瘤，72例卵巢上皮性癌组织和SKOV3、3AO、CaoV3卵巢癌细胞株Kilon基因mRNA的表达并用限制性内切酶一PCR的方法检测基因启动子中CpG岛甲基化的状况。结果 在卵巢上皮性癌组织中KilonmRNA的表达率（33．3％），显著低于正常卵巢组织和卵巢良性上皮性肿瘤组织的表达率分别为60．0％，76．5％。SKOV3、ca0V3和3AO均未见KilonmRNA表达。启动子甲基化在3种组织中的阳性率分别为0，11．8％和5．6％，卵巢癌与卵巢正常组织和良性肿瘤无显著差异。卵巢癌Kilon启动子HapII内切酶位点甲基化与mRNA失表达无相关性。SKOV-3、CAOV3和3AO均未发现甲基化。结论 卵巢上皮性癌细胞存在Kilon基因表达缺失。基因启动子CpG岛HapII酶切位点的甲基化与Kilon基因低表达无相关性。     

卵巢癌组织中Vasohibin基因表达与启动子区域甲基化的关系

目的探讨卵巢上皮性肿瘤中Vaso-hibin基因mRNA表达与临床特征及其启动子甲基化的关系。方法用RT-PCR检测10例良性卵巢上皮性肿瘤、8例交界性卵巢上皮性肿瘤及30例卵巢癌组织中VasohibinmRNA表达;用甲基化特异聚合酶链反应方法(MSP)检测Vasohibin启动子甲基化。结果各组标本中都有VasohibinmRNA表达,3组Vasohib-in表达的相对值良性卵巢上皮性肿瘤为0.65±0.11,交界性卵巢上皮性肿瘤为0.47±0.13,卵巢癌为0.34±0.14。卵巢癌组织中Vasohibin的表达量较交界性卵巢上皮性肿瘤组织显著降低,t=2.479,P=0.029;交界性卵巢上皮性肿瘤组织的表达量较良性卵巢上皮性肿瘤显著下降,t=3.198,P=0.006。在卵巢癌组织中,Vasohibin的表达与不同临床分期、不同分化程度以及有无淋巴结转移无关。良性卵巢上皮性肿瘤中未发现Vasohibin基因启动子甲基化;交界性卵巢上皮性肿瘤中2例发生启动子甲基化,卵巢癌中11例发生启动子甲基化,甲基化率36.7%。卵巢癌中启动子甲基化组织较未甲基化组织VasohibinmRNA表达显著降低,t=4.671,P=0.000。结论Vasohibin与卵巢癌发生存在明显相关性。Vasohibin启动子甲基化与其mRNA表达抑制密切相关,可能是Vasohibin在卵巢癌中低表达的最主要因素之一。     

卵巢上皮性癌TGFBI基因启动子甲基化与CyclinD1蛋白表达的关系

研究TGFBI基因启动子甲基化与CyclinD1蛋白表达在卵巢上皮性癌组织中关系,探讨TGFBI基因启动子甲基化在卵巢上皮性癌形成过程中的影响及意义。方法:用甲基化PCR的方法对20例正常卵巢上皮性组织（A组）,20例良性卵巢上皮性肿瘤组织（B组）,30例卵巢上皮性癌组织（C组）中TGFBI基因启动子甲基化进行检测,用免疫组化SP方法检测上述标本中CyclinD1蛋白的表达的情况。结果:1）C组TGFBI基因启动子甲基化频率高于B组及A组（P<0.05）;2）CyclinD1蛋白在卵巢上皮组织中的表达为:C组>B组>A组,各组之间差异均有统计学意义（P<0.016 7）;3）卵巢上皮性癌组织中CyclinD1蛋白表达增高与TGFBI基因启动子发生甲基化有关（r=0.505,P<0.05）。结论:TGFBI基因DNA启动子发生甲基化可能上调CyclinD1蛋白的表达,刺激细胞异常增殖。该机制可能参与卵巢上皮性癌的发生发展。      

上皮性卵巢癌组织中RASSF1A和BRCA1及p16基因异常甲基化检测及其临床意义的研究

目的：探讨RASSF1A、BRCA1和p16基因异常甲基化在上皮性卵巢癌发生及发展中的作用。方法：采用甲基化特异性PCR法检测63例上皮性卵巢癌组织和相应的41例盆腹腔转移灶及10例癌旁卵巢组织中RASSF1A、BRCA1和p16基因启动子区甲基化状态。结果：上皮性卵巢癌组织原发灶及转移灶中RASSF1A、BRCA1和p16基因启动子区甲基化发生率分别为49．2％、25．4％、20．6％及58．5％、26．8％、22．0％，均显著高于正常卵巢组织中的发生率，P值均〈0．05。RASSF1A基因启动子区异常甲基化的发生率在临床Ⅰ、Ⅱ期显著低于Ⅲ、Ⅳ期，Х^2=13．018，P〈0．0001；在高、中分化癌的发生率均显著低于低分化癌，Х^2=8．481，P=0．004；Х^2=8．195，P=0．004。结论：RASSF1A、BRCA1和p16基因异常甲基化与上皮性卵巢癌的发生及发展相关，RASSF1A基因异常甲基化与上皮性卵巢癌临床分期及分化程度相关。     

卵巢上皮性恶性肿瘤组织RASSF1A基因启动子区甲基化的研究

目的 探讨RASSF1A基因启动子区异常甲基化与卵巢上皮性恶性肿瘤发生、发展的关系。方法 应用甲基化特异性PCR方法,检测80例卵巢上皮性恶性肿瘤组织RASSF1A基因启动子区异常甲基化。结果 80例卵巢上皮性恶性肿瘤组织中,RASSF1A基因启动子区甲基化的发生率为52．5％,而相应痛旁正常组织中,RASSF1A基因启动子区均未发生甲基化（P〈0．05）。浆液性癌、黏液性癌和内膜样癌中,RASSF1A基因启动子区甲基化的发生率分别为54．2％、52．4％和45．5％,差异尤统计学意义。临床Ⅰ期、Ⅱ期卵巢上皮性恶性肿瘤RASSF1A基因启动子区甲基化的发生率分别为21．4％和16．7％,明显低于临床Ⅲ期（66．7％）和Ⅳ期（77．8％）。高分化组和中分化组RASSFlA基因启动子区甲基化的发牛率分别为34．5％和35．0％,均低于低分化组（80．6％）。结论 卵巢上皮性恶性肿瘤组织中存在RASSF1A基因启动子区的异常甲基化,甲基化与卵巢上皮性恶性肿瘤的临床分期和组织学分级有关。     

卵巢上皮性癌组织中DAPK基因启动子甲基化及其蛋白表达的研究

  目的  研究卵巢上皮性癌组织中DAPK基因启动子甲基化及其蛋白表达在卵巢癌发生发展过程中的作用及意义。  方法  应用甲基化特异性PCR(MSP)检测55例卵巢上皮性癌(恶性组)、25例卵巢交界性上皮性肿瘤(交界组)、30例卵巢良性上皮性肿瘤(良性组)、25例正常卵巢上皮组织(正常组)的石蜡包埋组织中DAPK基因启动子的甲基化情况。应用免疫组织化学链霉菌抗生物素蛋白-过氧化物酶连接(S-P)法检测上述蜡块组织中DAPK蛋白的表达情况。  结果  DAPK启动子在正常组、良性组、交界组、恶性组的甲基化率分别为0(0/25)、6.7%(2/30)、16.0%(4/25)、47.3%(26/55), 差异有统计学意义(P < 0.001), 恶性组的甲基化率高于其他三组; DAPK蛋白在正常组、良性组、交界组、恶性组的阳性表达率分别为96.0%(24/25)、90.0%(27/30)、48.0%(12/25)、30.9%(17/55), 差异有统计学意义(P < 0.001), 恶性组、交界组的阳性表达率均低于正常组和良性组; DAPK基因启动子甲基化和DAPK蛋白表达呈负相关。  结论  DAPK基因启动子甲基化导致基因沉默、失活, 引起蛋白表达下调或缺失, 并参与了卵巢上皮性癌的发生发展。      

MSP法检测胃癌组织中RASSF1A基因启动子区甲基化改变

目的:探讨抑癌基因RASSF1A启动子区CpG岛甲基化与胃癌及临床病理特征的关系.方法:采用甲基化特异性PCR(methylation-specific PCR,MSP)法检测60例胃癌组织及相应癌旁组织和30例对照组织中RASSF1A基因启动子区甲基化状态.结果:胃癌组织中RASSF1A基因启动子区CpG岛甲基化率为65.0%(39/60),显著高于癌旁组织6.7%(4/60),及对照组0%(0/30)(P＜0.01).胃癌组织中不同年龄、性别、分化程度及淋巴结转移与否的RASSF1A基因甲基化率的差异均无统计学意义.结论:胃癌中RASSF1A基因启动子区的高甲基化提示其与胃癌的发生密切相关,MSP法对RASSF1A基因启动子区甲基化的检测有望成为胃癌早期监测的重要方法.     

RASSF2基因表观失活与卵巢内膜样腺癌的相关性

目的:探讨RASSF2基因异常甲基化所导致的表观失活与卵巢内膜样腺癌的相关性.方法:甲基化特异性PCR技术及免疫组化技术检测46例卵巢内膜样腺癌组织RASSF2基因启动子区域的甲基化及组织中该基因的蛋白表达情况.结果:卵巢内膜样腺癌组织中RASSF2基因的甲基化发生率(24/46)及蛋白表达缺失发生率(25/46)均显著高于正常卵巢组织(0/10)及异位内膜组织(1/10),差异有显著的统计学意义(P＜0.05).内异症恶变相关卵巢内膜样腺癌组织中RASSF2基因甲基化发生率(7/11)与原发性卵巢内膜样腺癌组织中RASSF2基因甲基化发生率(17/35)无显著统计学差异(P＞0.05).RASSF2基因甲基化的组织中该基因蛋白表达缺失率96％(24/25)显著高于RASSF2基因非甲基化组织(2/41),RASSF2基因启动子区域异常高甲基化与其蛋白表达缺失具有相关性(P＜0.05).结论:RASSF2基因的表观失活可能在卵巢内膜样腺癌的发病机制中具有重要作用.     

Aberrant Methylation of RASSF2A in Tumors and Plasma of Patients with Epithelial Ovarian Cancer

Objective: The tumor suppressor gene, Ras-association domain family (RASSF)2A, is inactivated bypromoter hypermethylation in many cancers. The current study was performed to evaluate the methylationstatus of RASSF2A in epithelial ovarian cancer (EOC) tissues and plasma, and correlations with gene expressionand clinicopathologic characteristics. Method: We detected methylation of the RASSF2A gene in tissues andcorresponding plasma samples from 47 EOC patients and 14 patients with benign ovarian tumors and 10 withnormal ovarian tissues. The methylation status was determined by methylation-specific PCR while gene expressionof mRNA was examined by RT-PCR. The EOC cell line, SKOV3, was treated with 5-aza-2’-deoxycytidine (5-azadC).Results: RASSF2A mRNA expression was significantly low in EOC tissues. The frequency of aberrantmethylation of RASSF2A was 51.1% in EOC tissues and 36.2% in corresponding plasma samples, whereas suchhypermethylation was not detected in the benign ovarial tumors and normal ovarian samples. The expression ofRASSF2A mRNA was significantly down-regulated or lost in the methylated group compared to the unmethylatedgroup (p﹤0.05). After treatment with 5-aza-dC, RASSF2A mRNA expression was significantly restored in theSkov3 cell line. Conclusion: Epigenetic inactivation of RASSF2A through aberrant promoter methylation mayplay an important role in the pathogenesis of EOC. Methylation of the RASSF2A gene in plasma may be avaluable molecular marker for the early detection of EOC.     

Methylation Profile of BRCA1, RASSF1A and ER in Vietnamese Women with Ovarian Cancer

DNA methylation is considered a promising biomarkers for diagnosis of cancer in general and of ovariancancer in particular. In our study, we validated the accuracy of methylation specific polymerase chain reaction(MSP) to analyze the methylation pattern of BRCA1, RASSF1A and ER in 59 and 10 Vietnamese patients withepithelial ovarian cancer (EOC) and benign ovarian tumors, respectively. We found methylation of BRCA1,RASSF1A and ER in 11/59 (18.6%), 40/59 (67.8%) and 15/59 (25.4%) of EOC cases, while methylation of BRCA1was only detected in 2/10 (20%) benign ovarian patients. Forty five out of the 59 EOCs (78%) demonstratedmethylation at one or more genes. The methylation frequency of RASSF1A was significantly associated with EOC(p<0.0005). No significant association was observed between methylation status of these genes and the clinicaland pathological parameters of tumors collected from Vietnamese women suffering from ovarian cancer.     

Methylation of RASSF1A and CDH13 Genes in Individualized Chemotherapy for Patients with Non-small Cell Lung Cancer

Background: This study aimed to evaluate the methylation of RASSF1A and CDH13 gene promoter regions as a marker for monitoring chemotherapeutic efficacy with personalized medicine for patients with NSCLC, in the hope of providing a new direction for NSCLC individualized chemotherapy. Materials and Methods: 42NSCLC patients and 40 healthy controls were included. Patient blood samples were collected in the whole process of chemotherapy. Methylation of RASSF1A and CDH13 gene promoter regions was detected by the methylation specific polymerase chain reaction (MSP). Results: The rate of RASSF1A and CDH13 gene methylation in 42 cases of NSCLC patients was significantly higher than in 40 healthy controls (52.4% to 0.0%, 54.8% to 0.0%, p<0.05). After the chemotherapy, the hyper-methylation of RASSF1A and CDH13 genes in PR group and SD group decreased significantly (p<0.05), and was significantly different from that in PD group (p<0.05), but not as compared with healthy controls (P>0.05). With chemotherapy, RASSF1A and CDH13 promoter region methylation rate in 42 cases of patients showed a declining trend. Conclusions: The methylation level of RASSF1A and CDH13 gene promoter region can reflect drug sensitivity of tumors to individualized treatment.     

DBC1在卵巢癌中的表达及临床意义

目的:探讨乳腺癌缺失基因1（DBC1）在卵巢癌组织中的表达及与临床参数的相关性。方法:收集山东省聊城市人民医院手术切除的上皮性卵巢癌组织121例、交界性上皮性肿瘤组织40例和良性囊腺瘤组织55例,所有患者术前均未进行放疗、化疗等治疗。采用免疫组化技术检测DBC1在组织中的表达情况,并分析其与临床病理特征的相关性。结果:DBC1的阳性表达在卵巢癌组织中明显高于交界性囊腺瘤和良性囊腺瘤（P=0.001,P=0.000）,其表达水平与FIGO分期、分化程度及预后密切相关（P=0.033,P=0.022,P=0.037）。结论:DBC1在卵巢癌中可作为肿瘤促进因子发挥作用,并且与预后密切相关,可作为卵巢癌的肿瘤标志物之一。     

The RASSF1A tumor suppressor gene is commonly inactivated in adenocarcinoma of the uterine cervix.

PURPOSE: Development of adenocarcinoma (AC) of the uterine cervix, as well as squamous cell carcinoma (SCC), is strongly linked to infection by high-risk human papillomavirus (HPV) types. Human HPV E6 and E7 proteins inactivate the tumor suppressor genes p53 and retinoblastoma, respectively. However, additional genetic alterations may be required to maintain a malignant phenotype. Allelic loss at the short arm of chromosome 3 is one of the most frequent genetic changes found in cervical cancer and various other types of human cancer, including lung, breast, and ovarian cancer. This implies that a resident tumor-suppressor gene in this region is involved in the genesis of these tumors. RASSF1A, which is located at 3p21.3, is rarely inactivated by mutations but has been suggested as a target tumor suppressor gene on the basis of its frequent inactivation through promoter hypermethylation and loss of heterozygosity in a variety of primary human cancers. In the present study, we sought to determine whether epigenetic silencing of RASSF1A caused by hypermethylation of the promoter region plays a role in the development of uterine cervical cancer. Experimental Design: We studied 51 uterine cervical carcinoma samples. These 51 cases were comprised of 31 SCCs and 20 ACs. Real-time methylation-specific PCR system was used for the detection and quantitation of the bisulfite-converted methylated version of the RASSF1A promoter region. The 20 cases of cervical AC were also analyzed for the presence of oncogenic HPV 16 DNA using a PCR-based method. RESULTS: We found complete methylation of the RASSF1A promoter in 45% (9 of 20 samples) of AC cases. There was no promoter methylation observed in any of the 31 cases of SCC. We also correlated RASSF1A promoter hypermethylation to oncogenic HPV 16 infection. HPV 16 DNA was found in 3 of 9 (33%) AC tumors with RASSF1A promoter hypermethylation and 5 of 11 (45%) AC tumors without RASSF1A promoter hypermethylation. We could not demonstrate an inverse correlation between RASSF1A methylation and HPV 16 infection in AC of the uterine cervix. CONCLUSIONS: Hypermethylation of the RASSF1A promoter region is common in AC of the uterine cervix and rare in squamous carcinoma of uterine cervix. HPV infection does not correlate with RASSF1A methylation status in AC of the uterine cervix, but the absence of RASSF1A methylation in SCC of the uterine cervix coupled with the high incidence of HPV 16 infection in this subtype is in accord with previous reports. Our results suggest that epigenetic silencing of RASSF1A may play a role in the development of AC of the uterine cervix.     

Frequent hypermethylation of promoter region of RASSF1A in tumor tissues and voided urine of urinary bladder cancer patients

High frequency loss of 3p21.3 region where RASSF1A located was demonstrated in several tumors. We aimed to investigate the methylation status of RASSF1A and the frequency of LOH in 3p21.3 region in bladder cancer. Three bladder cancer cell lines, 40 cases of bladder TCC and 14 cases of paired voided urine samples were subjected to methylation analysis. By methylation specific PCR, complete methylation of promoter region of RASSF1A gene were detected in cell lines T24 and UMUC3. Demethylation treatment re-expressed RASSF1A in these 2 cell lines. Methylation of RASSF1A was also detected in 47.5% (19/40) of the TCC cases but not in 6 carcinoma in situ (CIS) or 6 normal urothelium samples. For LOH study, loss of 3p21.3 region was detected in 57.9% (11/19) of our cases. Interestingly, methylation of RASSF1A was found in 72.7% (8/11) of the cases with LOH but only in 12.5% (1/8) of the cases without LOH. Methylation of RASSF1A was detected in 50% (7/14) of voided urine samples, but not in normal control. It showed a higher sensitivity than conventional urine cytology in detecting cancer cells, especially for low grade cases. In conclusion, our results demonstrated a high frequency of RASSF1A methylation with frequent LOH in 3p21.3 region in bladder cancer. It suggested that it may be a potential tumor suppressor gene in this chromosomal region and can be silenced by promoter hypermethylation. Detection of aberrant gene methylation in routine voided urine was feasible and may provide a non-invasive and sensitive approach for cancer detection.     

Epigenetic modifications of RASSF1A gene through chromatin remodeling in prostate cancer.

PURPOSE: The RAS-association domain family 1, isoform A (RASSF1A) gene is shown to be inactivated in prostate cancers. However, the molecular mechanism of silencing of the RASSFIA gene is not fully understood. The present study was designed to investigate the mechanisms of inactivation of the RASSF1A gene through the analysis of CpG methylation and histone acetylation and H3 methylation associated with the RASSF1A promoter region. EXPERIMENTAL DESIGN: Methylation status of the RASSF1A gene was analyzed in 131 samples of prostate cancer, 65 samples of benign prostate hypertrophy (BPH), and human prostate cell lines using methylation-specific PCR. Histone acetylation (acetyl-H3, acetyl-H4) and H3 methylation (dimethyl-H3-K4, dimethyl-H3-K9) status associated with the promoter region in prostate cells were analyzed by chromatin immunoprecipitation (ChIP) assay. RESULTS: Aberrant methylation was detected in 97 (74.0%) prostate cancer samples and 12 (18.5%) BPH samples. The methylation frequency of RASSF1A showed a significant increase with high Gleason sum and high stage. The ChIP assays showed enhancement of histone acetylation and dimethyl-H3-K4 methylation on the unmethylated RASSF1A promoter. TSA alone was unable to alter key components of the histone code. However, after 5-aza-2'-deoxy-cytidine treatment, there was a complete reversal of the histone components in the hypermethylated promoter. Levels of acetyl-H3, acetyl-H4, and dimethyl-H3-K4 became more enriched, whereas H3K9me2 levels were severely depleted. CONCLUSIONS: This is the first report suggesting that reduced histone acetylation or H3K4me2 methylation and increased dimethyl-H3-K9 methylation play a critical role in the maintenance of promoter DNA methylation-associated RASSF1A gene silencing in prostate cancer.