脑肿瘤中P53基因突变与突变型P53蛋白表达的研究

采用聚合酶链反应－单链构象多态性（ＰＣＲ－ＳＳＣＰ）法对４１例脑肿瘤进行Ｐ５３基因突变的检测，并与抗突变型Ｐ５３蛋白单抗的免疫组化染色结果相对照，结果显示脑肿瘤中Ｐ５３基因突变率为３４．１％（１４／４１），胶质瘤为２８％（１０／３６）。Ｐ５３基因突变与突变型Ｐ５３蛋白表达具有高度一致性，且二者均与脑肿瘤的分化程度有关。Ｐ５３基因突变及蛋白的表达不仅出现在高恶度胶质瘤及转移癌，而且可出现在低恶度胶质瘤中，表明Ｐ５３基因的突变在脑瘤的发生、发展过程中起重要作用。     

脑胶质瘤中c—myc基因扩增,H—ras及p53基因突变

研究脑胶质瘤中癌基因c-myc的扩增、H-ras的突变及抑癌基因p53的5～8外显子的突变情况以及与胶质瘤的恶性程度的关系.采用差异性PCR(DPCR)及PCR-SSCP、PCR-RFLP等方法检测22例脑胶质瘤的基因突变情况.22例脑胶质瘤中c-myc扩增率为63.6%(14/22),H-ras的突变率为36.4%(8/22),p53的突变率45.5%(10/22).提示:癌基因c-myc的扩增及抑癌基因p53的突变与脑胶质瘤的恶性程度有关(P<0.05),而癌基因H-ras的突变则与脑胶质瘤的发生有关,与脑胶质瘤的恶性程度无关(P>0.05).各类型脑胶质瘤基因突变未发现不同(P>0.05),可能与标本量少有关.     

Survivin在脑膜瘤中的表达及其与p53、PCNA相关性研究

目的:探讨Survivin在脑膜瘤中的表达及与p53、PCNA相关性。方法:应用免疫组化SP法检测97例脑膜瘤组织、18例正常脑膜组织中survivin、p53、PCNA蛋白表达情况,结果进行统计学分析。结果:Survivin在脑膜瘤组织中表达的阳性率(65.9%)明显高于正常脑膜组织中的表达(0%)(P<0.001)。Survivin在脑膜瘤Ⅱ级(85.7%)和Ⅲ级(93.8%)中阳性表达率均明显高于脑膜瘤I级(51.7%)(P<0.001)。Survivin同p53表达共阳性23例,共阴性29例,两者的表达呈正相关(rs=0.451,P<0.01)。Survivin与PCNA蛋白表达共阳性45例,共阴性24例,两者的表达呈正相关(rs=0.640,P<0.01)。结论:Survivin是脑膜瘤形成和发展过程中重要的抗凋亡基因之一。Survivin与p53、PCNA在脑膜瘤的发生、增殖和恶化过程中可能起协同作用,其详细机制有待进一步研究。     

p53及其调控基因在胶质瘤和脑肿瘤干细胞中的作用

胶质瘤是成人最常见的原发性脑肿瘤,抑癌基因p53突变在胶质瘤中十分常见,但其机制尚未明确.近期研究显示:P53蛋白能控制肿瘤干细胞的自我更新并抑制其多能性.与胶质瘤相关的p53调控因子Pict1、Nanog、Bcl2L 12以及miRNA 则可能为胶质瘤及其干细胞提供新的基因治疗靶点.活化脑肿瘤干细胞中的P53联合现行治疗方案可能成为胶质瘤有效的治疗方法.     

脑肿瘤中P53蛋白的表达及Ki－67LI的相关性研究

利用突变型Ｐ５３蛋白的单抗及Ｋｉ－６７单抗对５０例冰冻标本进行检测，结果发现，脑肿瘤中突变型Ｐ５３蛋白的表达阳性率为４６％。低恶度胶质瘤、高恶度胶质瘤及转移癌中Ｐ５３蛋白表达的阳性率不同，分别为１８．２％、５３．８％及１００％。Ｐ５３蛋白表达阳性的肿瘤中高Ｋｉ－６７ＬＩ比例为７０％，其中位数及均数为１４．３％、２０．７６±１８．３（％），而无Ｐ５３蛋白表达的脑瘤中，ｋｉ－６７ＬＩ中位数及均数分别为１．３９及５．１９±９．０（％）。结果表明，突变型Ｐ５３蛋白的表达与脑肿瘤的组织类型，分化程度及细胞的增殖有关，而它的高表达又可能是肿瘤恶性表型或转移的标志之一。     

脑胶质瘤P53基因及其表达蛋白研究进展

P53肿瘤抑制基因的缺失、点突变是迄今发现的胶质瘤最常见的分子生物学改变。近来的研究表明,星形细胞瘤P53基因突变率较其它类型的胶质瘤高,胶质瘤P53基因突变多分布于第4—8外显子上,以错义突变为主,常常合并另一等位基因杂合性丢失。P53基因的缺失、突变和胶质瘤的病理级别、增殖能力有关。免疫组化研究显示,恶性胶质瘤常常存在P53蛋白过度表达。本文就此方面的进展及面临的问题作一概述。     

胸腺瘤中P53蛋白表达研究

目的:研究P53蛋白在胸腺瘤中的表现及临床意义。方法:用免疫组化染色法观察54例胸腺瘤中P53蛋白表达阳性细胞密度和分布。结果:发现P53表达与胸腺瘤浸润与否密切相关,26例恶性胸腺瘤(Ⅰ和Ⅱ型)中18例P53蛋白高度表达,而28例非浸润性胸腺瘤仅2例高度表达(P＜0.01),P53高度表达患者生存期较非高度表达者明显短。显示P53蛋白表达异常可作为胸腺瘤病变性质和判断病人预后的指标。54例胸腺瘤中49例P53蛋白表达阳性(90.7%)。结论:P53表达异常发生于胸腺瘤的早期。     

人脑胶质瘤P53、Bax蛋白表达变化及其与病人预后的关系

目的 探讨人脑胶质瘤组织P53、Bax蛋白变化及其与病人预后的关系。方法 选取2016年4月~2018年4月术后病理确诊的脑胶质瘤组织94例,选取同期颅脑损伤内减压术切除正常脑组织90例为对照组。采用免疫组化染色检测P53、Bax蛋白表达水平。随访2年记录总生存率。结果 脑胶质瘤组织P53蛋白表达阳性率（62.77%,59/94）明显高于对照组（15.56%,14/90;P<0.05）,而Bax蛋白表达阳性率（28.72%,27/94）明显低于对照组（68.89%,62/90;P<0.05）。低级别胶质瘤P53蛋白表达阳性率（40.0%,18/45）明显低于高级别胶质瘤（83.67%,41/49;P<0.05）,而Bax蛋白表达阳性率（55.56%,25/45）明显高于高级别胶质瘤（16.33%,8/49;P<0.05）。P53蛋白与胶质瘤病理级别呈正相关（r=0.745,P<0.05）,而Bax蛋白与胶质瘤病理级别呈负相关（r=-0.787,P<0.05）。多因素Cox比例回归风险模型分析结果显示P53表达阳性、Bax表达阴性是胶质瘤病人生存期较短的独立危险因素（P<0.05）。P53阳性表达胶质瘤病人2年累积生存率（69.49%,41/59）明显低于阴性表达组（88.57%,31/35;P<0.05）,Bax阳性表达胶质瘤病人2年累积生存率（92.59%,25/27）明显高于阴性表达组（70.15%,47/67;P<0.05）。结论 脑胶质瘤P53呈高表达,Bax呈低表达,二者与脑胶质瘤恶性程度有关,对脑胶质瘤预后评估有重要意义。     

P53和P57kip2在脑膜瘤中的表达及临床意义

目的探讨P53和P57kip2在脑膜瘤中的表达及临床意义。方法应用免疫组化SP法检测41例脑膜瘤组织和21例正常脑膜组织中P53和P57kip2蛋白的表达。结果在脑膜瘤中两者的阳性表达率:P53 48.78%,P57kip241.46%;P53在恶性脑膜瘤中的阳性率(75.00%)显著高于良性脑膜瘤及正常组织中的阳性率(P<0.05);P57kip2在恶性脑膜瘤中的阳性率(25.00%)显著低于于良性脑膜瘤及正常组织中的阳性率(P<0.05);P53与P57kip2在脑膜瘤中的表达呈负相关。结论 P53和P57kip2分别是脑膜瘤进展及预后判断的独立指标,多个指标联合检查用来估计患者预后指导意义更佳。     

P16与P53蛋白在脑胶质瘤中的表达及意义

目的:探讨P16与P53蛋白在人脑胶质瘤中的表达及与病理分级的关系。方法:采用免疫组化方法检测52例胶质瘤手术标本及2株人脑胶质瘤细胞系中P16与P53蛋白的表达状况,并分析其与该类肿瘤病理级别的关系。结果:随胶质瘤病理级别的升高P16蛋白的表达率逐渐降低,Ⅰ～Ⅳ级阳性率分别为75.0％、64.7％、42.8％和33.3％,低度恶性组(Ⅰ～Ⅱ级)与高度恶性组(Ⅲ～Ⅳ级)间有显著差异(P<0.05)。P53蛋白表达率随胶质瘤病理级别的升高有上升趋势。结论:P16及P53基因表达在胶质瘤恶性演变中有重要意义。     

Accumulation of wild-type p53 in astrocytomas is associated with increased p21 expression

Approximately one quarter of human astrocytomas show immunohistochemical positivity for p53 protein but lack p53 gene mutations, which could reflect either an accumulation of wild-type p53 protein or an inadequate sensitivity of mutation detection. Since wild-type p53 up-regulates p21 expression, increased p21 expression in those astrocytomas with p53 accumulation in the absence of mutations would argue that the protein was wild type in these tumors. We therefore compared p21 expression with p53 gene and protein status in 48 primary human astrocytomas. Single-strand conformation polymorphism analysis and direct sequencing of the p53 gene showed mutations in 11 tumors (22.9%), while immunohistochemistry revealed positive staining in 19 cases (39.6%). Those tumors with p53 immunopositivity in the absence of p53 mutation had significantly increased p21 expression when compared to either mutant p53 or p53-immunonegative cases. Neither p53 nor p21 status correlated with proliferation indices, as assessed by Ki-67 immunohistochemistry. These results support the hypotheses that functionally wild-type p53 accumulates in some astrocytomas, and that alternative cell cycle checkpoints (such as the p16 pathway) may be more important than p21 in regulating proliferation in astrocytomas. Received: 11 October 1996 / Revised, accepted: 17 January 1997     

人脑胶质瘤中Livin、p53的表达及其与肿瘤恶性程度的关系

目的 探讨Livin、p53在不同级别人脑胶质瘤中的表达及其与肿瘤恶性程度之间的关系.分析二者在胶质瘤细胞凋亡过程中的信号转导机制.方法 应用免疫组织化学技术检测Livin、p53蛋白在41例人脑胶质瘤和10例正常脑组织中的表达.结果 Livin、p53蛋白在10例正常脑组织中均不表达,在41例胶质瘤组织中表达率分别为87.8%和41.5%.Livin和p53蛋白在低级别胶质瘤中表达较低,在高级别胶质瘤中表达较高,两组比较差异有统计学意义(P＜0.05).Spearman等级相关分析显示,Livin蛋白与p53蛋白表达呈正相关(r=1.000,P＜0.01).结论 Livin和p53在人脑胶质瘤组织中表达上调,细胞凋亡受到抑制,引起肿瘤恶性增殖,与胶质瘤病程发展、恶性程度明显相关,这可能是胶质瘤恶性增殖的一个机制.     

Analysis of p53 gene mutations in low- and high-grade astrocytomas by polymerase chain reaction-assisted single-strand conformation polymorphism and immunohistochemistry

Using polymerase chain reaction-assisted single-strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses, mutations in the p53 tumor suppressor gene were examined in 19 low-and high-grade gliomas. By PCR-SSCP and nucleotide analyses, p53 gene mutation was seen in 7 gliomas. Out of the 7 mutations, 3 were located at the CpG site of the previously proposed hot-spot codons 248 and 273, 2 were at codons 171 and 214 and the other 2 were in intron 5, 1 at the splice acceptor site and the other in the vicinity of the splice donor site. The latter 4 mutations have not, or only rarely, been observed in gliomas or in other tumors. However, their effect on the structural and functional alteration of the p53 protein was suggested by positive intranuclear p53 immunostaining in neoplastic cells in 3 mutations including the 1 at the splice acceptor site. In connection with glioma grading, the p53 gene mutation was shown to have occurred in both low- and high-grade gliomas, often in most of the neoplastic cells, as suggested by lack of distinct normal bands and ladders in SSCP and direct sequencing, respectively. The absence of recurrence and malignant transformation over a considerably long postoperative time in our low-grade glioma cases suggested that the p53 gene mutation might not be sufficient for the progression from low- to high-grade gliomas. The frequency of detection of mutation was 7/19(37%) by PCR-SSCP, 8/19(42%) by immunohistochemistry and 10/19(53%) by both methods. The results of PCR-SSCP and immunohistochemistry were consistent in 14 cases(73.7%), but not in 5 cases(26.3%). Thus, the use of both methods was recommended to survey the occurrence of p53 gene mutation more accurately.Supported in part by the Fujisawa Foundation     

Correlation between histological grade and MIB-1 and p53 immunoreactivity in meningiomas

OBJECTIVE: Meningiomas for the most part are slow-growing benign tumors, but complete removal can be difficult and recurrence is an issue. The aim of this study was to re-evaluate tumors diagnosed as meningioma previously in our hospital, according to the latest World Health Organization classification. We also examined the relationships among parameters such as brain invasion, histological grade and Ki-67 and p53 expression in these tumors. MATERIALS AND METHODS: Meningioma biopsy specimens numbering 60 (48 grade I, 11 grade II, and 1 grade III tumors) were examined immunohistochemically using monoclonal antibodies for Ki-67 (MIB-1) and p53 protein. The MIB-1 labeling index (LI) for each tumor was calculated as a percentage based on the number of stained cells per total cells counted. The level of p53 expression in each sample was semiquantatively evaluated as < 1%, 1 - 10%, 10 - 70%, or > 70%. Any value > 1% was accepted as presence of p53 expression. RESULTS: Of the 60 meningiomas, 7 (11.7%) exhibited brain invasion. The mean MIB-1 LI values for the grade I and grade II tumors were 1.1% and 2.3%, respectively. The corresponding levels of p53 protein expression in these groups were 54.1% and 72.7%. The MIB-1 LI and the level of p53 expression in the one grade III meningioma were 6.7% and 10 - 70%, respectively. Histological grade was significantly correlated with MIB-1 LI and with p53 expression (p < 0.01 for both). Brain invasion was not correlated with histological grade, MIB-1 LI, or p53 expression. CONCLUSION: The results indicate that MIB-1 LI and p53 protein expression are good indicators of histological grade in meningioma and may be particularly valuable for distinguishing borderline atypical meningiomas. The number of cases was limited, but the findings also suggest that brain invasion is a prognostic parameter independent of grade, MIB-1 LI and p53 expression.     

RGS16与p53在人胶质瘤中的表达及相关性研究

目的 研究G蛋白信号调节子16(RGS16)与p53在人胶质瘤中表达及其相关性.方法 利用免疫组织化学链霉亲合素-生物素-过氧化物酶复合物(SABC)法检测42例胶质瘤标本中RGS16与p53的表达.结果 RGS16在10例胶质瘤旁正常脑组织有8例神经元阳性但胶质细胞阴性、42例胶质瘤中37例肿瘤细胞阳性,二者差异显著(P<0.05);p53在瘤旁正常脑组织中阴性,胶质瘤中15例阳性,差异明显(P<0.05);RGS16、p53表达均与病理分型、分级无关(P>0.05);其中,RGS16与p53共同阳性表达11例,共同阴性表达1例,Kappa检验二者表达呈负相一致(P<0.05).结论 RGS16在胶质瘤中高表达而与病理分级无关,推测RGS16可能在胶质瘤发生中起作用.另外,胶质瘤中RGS16与p53表达呈负相关.     

Accumulation of wild-type p53 in meningiomas

The p53 tumour suppressor gene contributes to the regulation of DNA repair and the initiation of apoptosis. Mutations of this gene and nuclear accumulation of its protein product are features of a large variety of turnours. A histological spectrum of meningiomas, including anaplastic examples and a meningosarcoma. was analysed for accumulation of the p53 protein and mutations in exons 4–9 of the p53 gene. No mutations were found, but 9134 (26%) tumours showed accumulation of the p53 protein. The p53-positive meningiomas came from across the histological spectrum and were not restricted to the anaplastic group. The accumulation of wild-type p53 in a proportion of meningiomas may reflect this gene's role in DNA repair, or its enhanced stability when bound to cellular proteins such as the mdm-2 gene product.     

A comparative immunohistochemistry of O6‐methylguanine–DNA methyltransferase and p53 in diffusely infiltrating astrocytomas

The DNA repair protein O⁶‐methylguanine–DNA methyltransferase (MGMT) removes mutagenic adducts from the O⁶ position of guanine, thereby protecting the genome against guanine : cytosine to adenine : thymine transition and, meanwhile, conferring tumor resistance to many anticancer alkylating agents commonly used in the treatment of malignant gliomas. Studies on the involvement of p53 protein in expression of the MGMT gene have provided conflicting results regarding the relation between p53 protein and MGMT gene expression. To examine the potential immunostaining pattern of MGMT expression and to evaluate the possible relationship between p53 and MGMT regulation, we assessed MGMT and p53 accumulation on 35 cases of diffusely infiltrating astrocytomas. With a few cases showing cytoplasmic staining, MGMT accumulation was mainly nuclear. The percentage of labeled tumor cells was lower in high‐grade astrocytomas than in low‐grade astrocytomas (P < 0.05). Additionally, p53‐immunopositive tumor cells were usually immunonegative to MGMT. Thus, it is suggested that MGMT expression is reduced during malignant transformation of diffusely infiltrating astrocytomas, and that mutant p53 protein might be associated with down regulation of the MGMT expression.