脑胶质瘤p 15 基因缺失及5′CPG 岛甲基化研究

 目的　探讨 p1 5基因变异及其与脑胶质瘤的发生、恶性进展的关系。方法　利用 PCR和 PCR- based甲基化检测技术检测了 56例脑胶质瘤中 p1 5基因外显子 1缺失及 5′CPG岛甲基化情况。结果　 43例高级别的脑胶质瘤中 ,1 4例发生了 p1 5基因缺失 ( 32 .6% ) ,而 1 3例低级别的脑胶质瘤中无一例发生 p1 5基因缺失 ,差异具有显著性 ( P<0 .0 5)。 1例低级别的脑胶质瘤、3例高级别的脑胶质瘤发生了 p1 5基因 5′CPG岛甲基化。结论　 p1 5基因异常可能参与脑胶质瘤的发生、恶性进展。基因纯合缺失是脑胶质瘤中 p1 5基因失活的主要机制.     

DELETION AND 5

　Objective To investigate the abnormality of p15 gene in brain glioma and the correlation of it with occurrence or malignant progression of brain glioma. Methods Deletion and 5’CPG island methylation of p15 gene were detected by the methods of PCR and PCR-based methylation in 56 cases of brain glioma. Results Out of 43 cases of high grade glioma, 14 cases were found to have homozygous deletion of p15E1, while none of the 13 cases of low grade glioma was found to have deletion of p15E1 (P<0.05). Methylation of 5’CPG Island of p15 gene was found only in four cases of glioma. Conclusion Abnormality of p15 gene may involved in the occurrence and malignant progression of brain glioma. Homozygous deletion of gene is the major mechanism of inactivation for p15 gene in brain glioma.     

脑肿瘤p16基因缺失，突变及5’CpG岛甲基化研究

目的：探讨不同种类的脑肿瘤P16基因变异及其与脑肿瘤的发生,发展的关系。方法：利用PCR,PCR－SSCP及PCR－based甲基化技术检测了56例胶质瘤,15例脑膜瘤及2例原发性脑淋巴瘤P16基因缺失,突变及5’CpG岛甲基化状况,结果：18例高病理级别的脑胶质瘤及1例原发性脑淋巴瘤发生P16基因缺失;6例脑胶质瘤及1例原发性脑淋巴瘤发生P16基因5’CpG岛甲基化,无1例发生P16基因突变。结论：P16基因失活可能参与脑胶质瘤的发生,恶性进展及原发性脑淋巴瘤的发生,P16基因缺失是P16基因失活的主要机制。     

STUDY OF DELETION OF P16 GENE IN THE PROGRESSION OF BRAIN ASTROCYTOMAS

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Homozygous deletion of the p16/MTS-1/CDKN2 gene in malignant gliomas is infrequent among Japanese patients.

We have analyzed the status of the p16/MST-1/CDKN2 gene in 63 brain tumors from Japanese patients. With quantitative multiplex polymerase chain reaction (PCR) assay using the exon 2 primers of the p16 gene and control chromosome 9qSTS primers, we found homozygous deletion of the p16 gene in 7 cases; in 1 out of 10 cases of anaplastic astrocytomas (WHO grade III), 6 out of 35 cases of glioblastoma multiformes (grade IV) but in none of the tumors of grade I or II. We also found mobility-shifted PCR products in 8 cases using the single-strand conformation polymorphism technique. DNA sequencing of the aberrantly migrated products revealed that 5 cases of glioblastoma multiforme had mutations which caused amino acid substitutions. We found one case with silent mutations and two cases with nucleotide changes in the non-coding region. The frequency of the alteration of the p16 gene, either homozygous deletion or mutation accompanied with amino acid substitutions, increased in malignant brain tumors (grade III and IV) compared with that in low grade tumors (grade I and II) (p=0.0275), suggesting possible role(s) of the gene in the progression of brain tumors. In addition, the low frequency of homozygous deletions shown in this study is quite different from previous reports that demonstrated frequently deleted p16 gene in malignant gliomas from Caucasian patients. We have also shown the presence of heterogeneous cell populations within the glioblastoma masses based on the variety of the mutated p16 sequences. The present study, therefore, suggests a possible racial difference in the mechanism of the tumorigenesis and a heterogeneity of malignant gliomas developed during the tumor progression.     

胶质瘤患者血浆与肿瘤组织P16基因甲基化的检测及意义

Objective:To explore the clinical significance of methylation status of promoter CpG island of p16 gene in glioma tissue and plasma.Methods:Methylation specific polymerase chain reaction (MSP) was used to determine the methylation status of the promoter for p16 gene within glioma tissue and plasma.Immunohistochemicel method (SP) was used to analyze the expressions of p16 and Ki-67 proteins.Results:Hypermethylation was found in 17/40 (42.5%) of brain gliomas,in comparison with 11/40 (27.5%) plasma specimens (x2 = 1.9780,P = 0.1596).Loss of p16 expression was associated (P = 0.0229) with hypermethylation of CpG island of promoter regions.Hypermethylation of p16 gene CpG island was significantly related to the increase of malignant grade of brain glioma (Tissue:X2 = 11.4288,P = 0.0007;Plasma:X2 = 8.9439,P = 0.0028).The Ki-67 index increased significantly (P＜0.05) in brain gliomas methylated in contrast to those unmethylated.Conclusion:P16 hypermethylation may be one of the major mechanisms of tumorigenesis of gliomas.Methylated tumor-specific DNA may be as a plasma biomarker for prognosis in patients with glioma.     

乳腺癌组织中p16基因变异及CpG岛甲基化状态的研究

目的探讨p16基因在乳腺癌中的纯合缺失、突变和甲基化的改变及与乳腺癌发生、发展的关系.方法采用PCR缺失分析、PCR-SSCP及甲基化敏感内切酶-PCR分析方法检测p16基因在39例乳腺癌组织变化状况,并结合临床病理资料进行分析.结果39例乳腺癌组织有6例出现p16基因纯合缺失,3例发生p16基因突变,p16基因变异频率为15.4%,5'CpG岛11例发生甲基化,甲基化率为28.2%.10例良性乳腺病组织中未发现p16基因改变和甲基化.p16基因变异频率、甲基化状态与临床分期和淋巴结转移密切相关.结论p16基因变异、甲基化是乳腺癌中常见的分子改变,它们在乳腺癌的发生、发展过程中扮演着重要的角色.     

建立人脑胶质瘤恶性进展相关基因表达谱

目的：建立人脑胶质瘤恶性进展相关基因表达谱。方法：用微阵列技术对同一胶质瘤患者初发(WHOⅡ级)、复发(WHOⅢ级)和再发(WHOⅣ级)的3次手术标本中基因差异表达情况进行检测,并以第3次手术时切取的正常脑组织作为对照。结果：全组共获取16363个数据。3份肿瘤标本中,表达差异≥3倍的基因共197条。将含正常脑组织在内的4份标本进行两两比较,表达差异≥3倍的基因共489条(上调193,下调296)。再将已知功能的109条基因按出现频率排列,由高到低依次为发育、代谢、分化、信号传导、DNA结合转录、细胞受体、免疫、DNA合成修复重组、离子通道运输、蛋白翻译合成、细胞骨架运动、应激、原癌和抑癌、细胞凋亡、细胞周期相关基因。结论：从处于恶性进展不同阶段的人脑胶质瘤手术标本中发现了197条表达差异≥3倍的基因,同时经生物信息学分析,发现17条候选新基因,它们在胶质瘤发生与发展的分子机制中起重要作用。     

RASSF1A基因在胶质瘤组织中甲基化研究及临床意义

目的：探讨胶质瘤组织及脑正常组织中抑癌基因RASSF1A启动子区甲基化程度及与临床特征的关系。方法：采用甲基化特异性聚合酶链反应（MS-PCR）方法检测46例脑胶质瘤（其中星形细胞瘤19例,室管膜瘤16例,胶质母细胞瘤11例）及6例脑正常组织中RASSF1A基因启动子区甲基化状态。并对RASSF1A基因启动子区甲基化发生情况与临床各因素之间的关系进行分析。结果：（1）46例脑胶质瘤组织DNA标本中RASSF1A基因启动子区甲基化发生率为65．2％（30／46）;6例脑正常组织中RASSF1A基因未发生甲基化;RASSF1A在胶质瘤和脑正常组织之间发生甲基化率比较差异有显著性（P=0.017）。在46例脑胶质瘤中RASSF1A有30例发生甲基化,其中低级别组14例（14／26）,高级别组16例（16／20）,两组之间甲基化率比较无明显差异（P〉0．05）。其中星形细胞瘤、室管膜瘤、胶质母细胞瘤中甲基化发生率分别为63．2％（12／19）、68、8％（11／16）、63．6％（7／11）,各组之间甲基化发生率比较均无统计学意义（P=0．211）。（2）RASSFIA基因启动子区甲基化程度与脑胶质瘤病理分型、肿瘤大小之间无显著相关性。结论：RASSF1A在胶质瘤中有甲基化发生,在脑正常组织中未发生甲基化,检测胶质瘤中RASSF1A基因启动子区甲基化情况对临床判断肿瘤发生发展有指导意义。     

恶性淋巴瘤中p16基因的缺失及甲基化

目的：研究恶性淋巴瘤中ｐ１６基因缺失、甲基化发生的频率及其在淋巴瘤发生、发展中的作用,并研究其与淋巴瘤恶性度的关系。方法：收集７８例新鲜淋巴瘤标本及９例反应性增生的标本,用聚合酶链反应（ＰＣＲ）扩增ｐ１６基因第１、第２外显子,检测等位基因纯合性缺失,用限制性内切酶－ＰＣＲ方法检测ｐ１６基因甲基化。结果：ｐ１６基因在恶性淋巴瘤中的缺失率为１１．５％,甲基化率为２６．９％;９例反应性增生未见ｐ１６基因     

胶质瘤MGMT启动子甲基化及其临床意义

目的 分析O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）基因启动子甲基化状态及其与胶质瘤临床病理特征、预后的关系。方法 收集2012年1月至2013年6月间行手术治疗的70例胶质瘤组织和14例非肿瘤患者正常脑组织，采用甲基化特异性 PCR法（MSP）检测MGMT甲基化水平，分析其与胶质瘤临床病理特征的关系。比较不同MGMT甲基化状态的高、低级别胶质瘤患者的总生存（OS），Cox比例风险回归模型分析影响低级别胶质瘤患者的OS的因素。结果 70例胶质瘤患者中48例（68.6％）MGMT基因启动子甲基化，而正常脑组织标本中仅2例（14.3％）MGMT甲基化，差异有统计学意义（P＜0.05）。MGMT甲基化与年龄、性别、肿瘤类型、KPS评分、p53和Ki-67表达无关（P＞0.05）；与病理分级有关（P＜0.05）。低级别脑胶质瘤患者中，MGMT甲基化患者中位OS为30个月，明显长于非甲基化者的11个月，差异具有统计学意义（P＜0.05）。单因素分析显示WHO病理分级、烷化剂化疗、MGMT甲基化与低级别脑胶质瘤患者OS有关（P＜0.05）。多因素分析WHOⅡ级、未接受烷化剂化疗、MGMT非甲基化是影响低级别胶质瘤患者OS的独立危险因素（P＜0.05）。结论 MGMT甲基化与胶质瘤的发生、发展有关，在判断胶质瘤恶性度、评估预后及指导临床治疗方面具有一定的价值。     

半巢式甲基化特异性PCR在急性淋巴细胞白血病患者p15基因甲基化检测中的应用

 【摘要】 目的 探讨半巢式甲基化特异性PCR（hn-MSP）的特性并了解p15基因甲基化和缺失在急性淋巴细胞白血病（ALL）发病中可能起到的作用。方法 运用hn-MSP方法和基因组硫化修饰PCR（BSP）后直接测序分析在25例初诊或复发不同阶段ALL患者以及部分恶性血液病细胞株中p15基因的甲基化和缺失状态,以10名健康者或非恶性血液病患者为对照组。以Molt-4细胞株为阳性对照,以对照组单个核细胞为阴性对照,分析hn-MSP方法的敏感性和特异性。结果　hn-MSP产物克隆测序结果与BSP结果一致,hn-MSP检测p15基因甲基化敏感性可达到1×10－5。hn-MSP检测,25例ALL患者p15基因甲基化发生率为68.0 ％（17例）;25例ALL患者中3例p15基因外显子1缺失,对照组p15基因无甲基化或缺失。结论　p15基因甲基化状态在ALL患者有较高的检出率,hn-MSP在分析p15基因甲基化状态上具有较高的特异性和敏感性。     

p14<Superscript>ARF</Superscript> promoter region methylation as a marker for gliomas diagnosis

Methylation in the promoter region is one of the mechanisms through which tumor suppressors are inactivated, resulting in tumorigenesis and/or tumor progression. Herein, we studied the methylation status in the promoter region of the p14^ARF tumor suppressor gene in 33 brain tissues isolated from glioma patients (astrocytomas) and compared to 12 brain tissues isolated from autopsy donors using methylation-specific polymerase chain reaction (MSP). The correlation between the expression of P14 and P53 was investigated using immunohistochemistry (IHC). The average percentage of methylation in the promoter region of p14^ARF gene in brain samples from glioma patients is 39.4%, while 0 from autopsy donors. No difference in the methylation level between low-grade and high-grade gliomas was detected. The methylation status has no correlation with the prognosis in glioma patients. A significant correlation between the expression of mutant form of TP53 and the grade of the glioma was established. Furthermore, there was a negative correlation between methylation of the p14^ARF promoter and the expression of the mutant form of TP53. Therefore, our data suggest that methylation in the promoter region of the p14^ARF gene may be used as a biomarker for the diagnosis of gliomas.     

胶质瘤细胞诱导分化相关基因在胶质瘤组织中的表达

目的 利用已经建立的胶质瘤细胞诱导分化相关基因表达谱，筛选胶质瘤恶性进展相关基因。方法 按分子生物学实验要求，收集经病理确诊的不同恶性程度胶质瘤手术标本，应用反向多点杂交技术制作分子探针，与96个相关基因组成的小芯片杂交检测在不同恶性级别胶质瘤手术标本中的表达情况。结果共有8个基因在各个恶性级别胶质瘤中均呈高表达；有14个基因随胶质瘤恶性程度升高而表达频率呈上升趋势；有6个基因随胶质瘤恶性程度升高表达频率呈下降趋势；筛选到可能与胶质瘤恶性进展有关的新基因有DIP1、RPS7、CLK2、WWOX／FOR、GRIM-19等基因。结论 本研究制作的胶质瘤细胞分化相关基因小芯片，在不同级别胶质瘤组织标本中检测到的表达情况，可进一步用于胶质瘤恶性进展的分子机制研究。     

P21~(WAF1/CIP1)、P16蛋白表达与人脑神经胶质瘤的相关分析

背景与目的:探讨P21WAF1/CIP1、P16两种抑癌基因与人脑神经胶质瘤恶性程度的关系。材料与方法:采用SABC免疫组织化学方法对98例人脑胶质瘤组织及12例正常脑组织标本中P21WAF1/CIP1和P16的表达进行检测,并进行相关分析。结果:P21WAF1/CIP1和P16阳性表达率在人脑胶质瘤中分别为58.16%和42.86%,与正常脑组织中的表达情况差异有统计学意义;P21WAF1/CIP1蛋白和P16蛋白阳性表达率均随着胶质瘤的恶性程度的增高而降低;P21WAF1/CIP1蛋白和P16蛋白可协同表达。结论:P21WAF1/CIP1与P16蛋白的阳性表达率及协同表达率可在一定程度上反映胶质瘤细胞的恶性生物学行为,可以作为一项判断其恶性程度的有效指标。     

周期蛋白依赖性激酶1在胶质瘤组织中的表达及其沉默对胶质瘤细胞恶性表型的影响

目的探讨周期蛋白依赖性激酶1(CDK1)在胶质瘤组织中的表达及其沉默对胶质瘤细胞恶性表型的影响。方法利用自建的人脑胶质瘤体外细胞系SHG44及其移植瘤组织、脑肿瘤干细胞、神经干细胞、不同恶性程度的胶质瘤手术标本构建组织芯片,免疫组化染色检测其CDK1蛋白表达;应用RNA干扰技术使CDK1在SHG44细胞及其移植瘤组织中沉默,观察其随后发生的表型变化。结果CDK1在临床标本中随胶质瘤恶性程度升高表达强度增加,Ⅰ-Ⅳ级的阳性表达率分别为22.2%、40.0%、69.6%和78.6%(P=0.01)。体外培养的人脑胶质瘤SHG44细胞球体和裸小鼠皮下移植瘤CDK1表达强度均较高,而神经干细胞和脑肿瘤干细胞球体表达强度低,在细胞增殖活性高的人胚胎脑组织和裸小鼠骨髓中CDK1亦高表达,但在正常成人脑组织低表达。C1和C3体外转染SHG44细胞后,将细胞周期阻滞在G2/M期,而且诱导了凋亡,细胞凋亡率分别上升至27.8%和36.5%。CDK1沉默的裸鼠皮下移植瘤瘤重明显降低,细胞凋亡率为57.1%,明显高于对照组(8.5%)。结论CDK1的高表达呵促进胶质瘤的发生和发展,CDK1沉默后的肿瘤细胞恶性表型可得到控制,CDK1可作为胶质瘤病因分子行进一步研究。     

A Comparative Study of Glioma Cell Lines for p16, p15, p53 and p21 Gene Alterations

A total of 10 glioma cell lines were examined for alterations of the p16, p15, p53 and p21 genes, which are tumor suppressor genes or candidates with direct or indirect CDK-inhibitory functions. Genetic alterations (deletions or mutations) were frequently seen in the p16, p15 and p53 genes in these cell lines, but not in the p21 gene. When the states of the p16, p15 and p53 genes were compared among cell lines, all the cell lines showed abnormalities in at least 1 gene, often in 2 or 3 genes coincidentally, suggesting that dysfunction of these genes is closely related to glioma cell growth. Although alteration of all 3 genes was most frequent, there were cell lines having either p16/p15 or p53 or p16 and p53 gene alterations, suggesting that the time order of these genetic alterations was variable depending on the cell line. Among cell lines examined, one with homozygous p53 gene deletion seemed of particular practical value, since such a cell line might be useful in various studies, including investigation of the functions of various mutant p53 genes in the absence of heteromeric protein formation. On examination of the primary tumor tissues, the same alterations of the p16/p15 and p53 genes as detected in the cell lines were demonstrated in all 6 cases examined: p16/p15 gene deletion in 1, p16 gene mutation in 1 and p53 gene mutations in 5 cases. This suggested that the p16/p15 and the p53 gene alterations and their combinations in at least some glioma cell lines reflected those in the primary glioma tissues.     

Association of p53 gene mutation with decreased chemosensitivity in human malignant gliomas

Loss of p53 function is involved in tumorigenesis of various human cancers, but the relation between mutation of the p53 tumor-suppressor gene and the chemo- and radiosensitivity of tumors remains unclear. Mutated p53 gene in malignant glioma is often associated with progression and recurrence of malignancy, and these events are closely linked with increased resistance to both chemotherapy and radiation. We have examined the status of the p53 gene in malignant gliomas obtained from 34 patients (glioblastoma: 29 cases, anaplastic astrocytomas: 5 cases). The chemosensitivities of these specimens using 28 kinds of anti-cancer agents were determined using an in vitro assay system. Overall, 12 mutated cases of p53 gene were found in malignant glioma samples. The mean numbers of effective agents were 0.58 for the tumor samples with p53 mutations and 5.00 for tumors without mutations. Our data indicate that p53 gene mutation predisposes to decreased cell killing via chemotherapy in malignant gliomas. © 1996 Wiley-Liss, Inc.     

Primary malignant lymphoma of the brain: frequent abnormalities and inactivation of p14 tumor suppressor gene

Ten primary central nervous system lymphomas (PCNSL, brain lymphomas) were examined for p14 gene exon 1beta deletion, mutation and methylation by Southern blot analysis, nucleotide analysis of polymerase chain reaction clones and Southern blot-based methylation assay. In Southern blot analysis, from the signal densities of the hybridized bands and their similarities to those of exons 2 and 3 in our previous quantitative study, we found that exon 1beta was homozygously deleted in four cases, hemizygously deleted in five cases and not deleted in one case. Thus, the same deletion patterns covered the entire p14 gene for all cases except for one case, which suggested the hemizygous deletion of exons 1beta and 2 and homozygous deletion of exon 3. In addition, although exon 1beta mutation is rare in various tumors, we detected a missense mutation (L50R) in one case with a hemizygous deletion. Methylation of the 5'CpG island of the p14 gene was not suggested for any case without homozygous deletion. Our observation of frequent p14 gene abnormalities (90%) and inactivation (40-60%) was in striking contrast to the same pathological subtype of systemic lymphoma in which p14 gene abnormalities and inactivation were infrequent, suggesting a difference in carcinogenesis between PCNSL and systemic lymphoma.     

INPP4B和PTEN在人脑胶质瘤中的表达及意义

目的:检测磷脂酰肌醇4-磷酸酶Ⅱ型（inositol polyphosphate 4-phosphatase type Ⅱ,INPP4B)和磷酸酯酶与张力蛋白同源物（phosphatase and tensin homolog deleted on chromosome ten,PTEN)在人脑胶质瘤中的表达情况及二者的相关性,希望对胶质瘤的诊断分级、预后判断及治疗等方面提供理论依据。方法:采用免疫组织化学法（IHC）和实时荧光定量PCR（qRT-PCR）法分别测定25例正常脑组织和60例不同级别胶质瘤中INPP4B和PTEN蛋白及mRNA的表达情况。结果:在IHC、qRT-PCR中显示:INPP4B、PTEN在正常脑组织组和低级别胶质瘤组、高级别胶质瘤组三组间表达差异均有统计学意义（P＜0.05）;低级别胶质瘤组中 INPP4B、PTEN表达均高于高级别胶质瘤组（P＜0.05）,正常脑组织组中 INPP4B、PTEN表达均高于低级别胶质瘤组和高级别胶质瘤组（P＜0.05）。INPP4B与PTEN mRNA在正常脑组织、低级别胶质瘤、高级别胶质瘤三组中表达呈正相关（P=0.000）。结论:INPP4B与PTEN的表达水平均与胶质瘤的恶性级别呈负相关,随着胶质瘤恶性程度的增高二者的表达水平下降。INPP4B与PTEN在胶质瘤中的表达水平具有正相关性,推测其可能在抑制胶质瘤的发生、发展、侵袭增殖等方面具有协同作用。