人脑肿瘤组织中SV40感染及其临床意义

目的 探讨猴病毒40（SV40）与人脑肿瘤发病的关系。方法 采用聚 一等奖反应（PCR）和原杂交（ISH）同时检测30例正常人脑组织和198例人及脑肿瘤组织以及SHG44和BT3 25两株人脑胶质瘤细胞系中SV40 DNA充列;并对SV40 DNA阳性肿瘤细胞采用免疫共沉淀和Western blot检测大T抗原（Tag）的表达及Tag-RB复合物的存在。结果 人脑肿瘤组织PCR SV40 DNA阳性率为48.5％（96／198）,其中胶质瘤47.2％（42／89）,脑膜瘤48.8％（21／43）,脑垂体腺瘤51. 4%(18/35),神经鞘瘤43.8％（7／16）,先天性肿瘤53.3％（8／15）,正常人脑组织PCR SV40 DNA阳性率为6.7％（2／30）。SHG44及BT325两株细胞中也分别检测出SV40的DNA序列。人脑肿瘤组织SV40 DNA阳性率显著高于正常人脑组织（P＜0.01）。经ISH,仅在96例PCR SV40 DNA阳性的及脑肿瘤组织中检出87例阳性,2例SV40 DNA阳性的正常人脑组织中1例ISH阳性,SHG44及BT325两株细胞ISH SV40 DNA均阳性。SV40 DNA定位于肿瘤细胞核,阳性细胞呈弥温或片灶状分布。96人列SV40 DNA阳性脑瘤组织Tag表达阳性75例,所有Tag表达阳性瘤组织均发现Tag与RB形成特异性复合物。结论 人脑肿瘤组织中存在SV40感染,提示SV40感染与有脑肿瘤有关;在人脑肿瘤组织中Tag广泛表达,Tag可能是SV40在有禽肿瘤发生发展中起作用的重要因素,S V40 Tag与RB形成特异性复合物Tag-RB,导致RB活性,有是SV40致人脑肿瘤发生的一个重要机理。     

星形细胞肿瘤表皮生长因子受体与p53基因的异常表达

目的研究星形细胞肿瘤中癌基因表皮生长因子受体（EGFR）过表达与抑癌基因p53突变、表达与肿瘤病理类型、恶性程度及两者的相互关系。方法对37例不同恶性程度的星形细胞肿瘤及6例正常脑组织,采用免疫组织化学、逆转录聚合酶链反应（RT—PCR）方法检测EGFR的表达;采用免疫组织化学、PCR—SSCP及DNA测序方法检测同一标本的p53基因突变和异常表达,分析它们的异常改变和内在联系。结果p53突变率在弥漫性星形细胞瘤、间变性星形细胞瘤、原发性胶质母细胞瘤、继发性胶质母细胞瘤分别为1／10,4／19（21．1％）,4／6和2／2,而EGFR过表达分别为5／10,10／19（52．6％）,5／6和2／2。随着胶质瘤级别增高,p53积聚与EGFR过表达在同一标本中发生率升高。结论在低度恶性胶质瘤中p53基因突变少见,EGFR过表达不少见;在原发性和继发性胶质母细胞瘤中p53基因突变及EGFR过表达均常见。提示p53与EGFR分子通路可能对胶质瘤的恶性进展不是相互排斥而是协同产生促进作用。     

ATRX在胶质瘤诊断及患者预后评估中的应用北大核心CSCD

目的探讨中国成人幕上胶质瘤中ATRX和p53基因突变在胶质瘤诊断及预后评估中的指导价值。方法选择整合诊断为WHOⅡ级、Ⅲ级的星形细胞瘤,IDH突变型;弥漫性星形细胞瘤,IDH野生型;WHOⅡ级、Ⅲ级的少突胶质细胞瘤,IDH突变型伴1p／19q共缺失,合计83例。采用免疫组织化学染色法检测ATRX蛋白失表达及p53蛋白过表达情况。分析两者的相关性及其与患者总生存期的关系。结果WHOⅡ级、Ⅲ级星形细胞瘤,IDH突变型及WHOⅡ级、Ⅲ级少突胶质细胞瘤,IDH突变型伴1p／19q共缺失的病例中的ATRX失表达率为85．19％（23／27）和0（0／53,P〈0．01）。在ATRX失表达病例中69．57％（16／23）同时存在p53过表达,二者密切相关（P〈0．01）。生存分析结果提示存在ATRX失表达、p53阴性的患者的总生存期长（P=0．013）。结论ATRX基因突变是较低级别星形细胞起源肿瘤的分子遗传特征之一,可以协助p53用于星形细胞瘤的诊断。ATRX联合p53基因突变检测可用于指导胶质瘤的预后评估。     

原发性脑瘤的分子遗传学研究进展

［摘要］ 原发性脑瘤是发生于神经系统常见的疾病，高度恶性的胶质瘤占原发性脑瘤的40%，主要分为I型胶质母细胞瘤（继发性胶质母细胞瘤）和II型胶质母细胞瘤（原发性胶质母细胞瘤），二者的产生有着不同的遗传学改变。I型胶质母细胞瘤的产生途径是从一种恶性程度较低的星形细胞瘤（II级，主要为p53基因突变和血小板来源的生长因子/受体过表达）至恶性的间变型星型细胞瘤（III级，主要为Rb基因突变，CDK4基因扩增，9p、11p、13q和19q的等位基因缺失），再到胶质母细胞瘤（IV级，最常见的遗传学改变是7号和20号染色体的获得,10号染色体的丢失以及PTEN和LRRC4基因的缺失，PDGFα及其受体的过表达）的渐进的发展过程；而II型胶质母细胞瘤则是一种没有恶性程度渐进过程的原发性胶质母细胞瘤，表皮生长因子受体基因的扩增是最常见的遗传学改变。     

CIC蛋白失表达在少突胶质细胞肿瘤诊断及预后判断中的意义北大核心CSCD

目的探讨CIC蛋白失表达在少突胶质细胞肿瘤中作为预测染色体lp／19q共缺失初筛检测方法的可行性及其对预后的影响。方法回顾性分析首都医科大学宣武医院病理科113例形态学具有少突胶质细胞瘤特征的胶质瘤,分别进行染色体lp／19q共缺失荧光原位杂交（FISH）检测及CIC蛋白免疫组织化学标记。分析CIC蛋白失表达与染色体1p／19q共缺失的相关性,并探讨其与预后的关系。结果在113例组织学诊断为少突胶质细胞肿瘤中,CIC蛋白失表达率为59．3％（67／113）,不同的组织学类型中失表达率不同,在只含有少突胶质细胞成分的肿瘤中失表达率（85．7％．42／49）比混合性的胶质瘤中（39．1％,25／64）高（P〈0．01）。CIC蛋白失表达预测1p／19q共缺失的敏感性和特异性分别为76．1％（54／71）和71．1％（27／38）,假阳性率和假阴性率分别为16．9％（11／65）和38．6％（17／44）。按照2016版（（WHO中枢神经系统肿瘤分类第4版修订版》,本组病例中63例整合诊断符合少突胶质细胞瘤／间变型少突胶质细胞瘤,IDH突变及1p／19q共缺失;CIC蛋白失表达率为81．0％（51／63）,其预测1p／19q共缺失的敏感性和特异性分别提高至81．0％（51／63）和76．9％（20／26）,假阳性率和假阴性率分别降至10．5％（6／57）和37．5％（12／32）。此时,应用Kaplan—Meier法分析CIC蛋白失表达对预后的影响,发现CIC蛋白失表达组比阳性表达组预后稍好,但二者差异无统计学意义（总生存期：P=0．218;无进展生存期：P=0．249）。结论利用免疫组织化学检测CIC蛋白失表达情况,可以作为染色体1p／19q共缺失的一种初筛检测方法。CIC蛋白失表达与预后无关。     

β-1,4-半乳糖苷键在星形胶质细胞瘤中的表达特征

目的研究β-1,4-半乳糖苷键在各型人脑星形胶质细胞瘤中的表达变化特征。方法分别提取人正常脑及星形胶质细胞瘤蛋白质,通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）,考马斯亮蓝（CBB）染色。并利用特异识别β-1,4-半乳糖苷键的蓖麻凝集素-Ⅰ（RCA-Ⅰ）,经letin blot和组织化学方法分析β-1,4-半乳糖苷键在各型人脑星形胶质细胞瘤中的表达变化和表达定位。结果CBB染色结果显示,人正常脑及星形胶质细胞瘤的蛋白质组成相似。RCA-Ⅰ letin blot显示：星形胶质细胞瘤组织半乳糖基化较正常脑组织有升高趋势,并且有-61kD的蛋白在胶质瘤组织中被半乳糖基化。组织化学方法表明：β-1,4-半乳糖苷键散在表达于正常脑组织和各级胶质瘤组织中,随着肿瘤分级增高,表达β-1,4-半乳糖苷键的细胞增多：Ⅰ、Ⅱ、Ⅲ和Ⅳ平均RCA-Ⅰ染色阳性率分别为15％、21％、28％和41％,而正常脑组织平均RCA-Ⅰ染色阳性率为8％。结论β-1,4-半乳糖苷键的表达与人脑星形胶质细胞瘤恶性程度密切相关,为分析β-1,4-半乳糖苷键及其相关糖基转移酶在恶性胶质瘤中的发病和诊治意义奠定基础。     

CD34在难治性癫痫相关脑肿瘤中的表达及鉴别诊断意义

目的 探讨CD34在难治性癫痫相关脑肿瘤中的表达情况及其在鉴别诊断中的应用价值.方法 应用免疫组织化学EnVision法检测CD34在54例难治性癫痫相关脑肿瘤中的表达情况,包括50例混合性神经元一胶质肿瘤和4例多形性黄色瘤型星形细胞瘤(PXA).其中前者包括2l例神经节细胞胶质瘤(GG),8例胚胎发育不良性神经上皮瘤(DNT)和21例组织学形态介于胶质神经元错构性病变和混合性神经元-胶质肿瘤之间具有过渡特征的病变.另外9例胶质瘤的表达情况作为对照,包括4例胶质母细胞瘤和5例混合性星形-少突胶质细胞瘤.结果 CDM在21例GG中的20例、8例DNT中的1例、21例具有过渡特点的混合性神经元-胶质肿瘤/病变中的16例及4例PXA中的3例的肿瘤区域为阳性;在伴有肿瘤周边组织的病例中,18例GG中的9例、18例具有过渡特点的混合性神经元-胶质肿瘤/病变中的6例及3例PXA中的1例的肿瘤周边组织为阳性,定位于胞质、胞膜和细胞突起.CD34仅在1例胶质母细胞瘤病变区域少数细胞呈阳性.CD34在不同类型肿瘤病变和周边脑组织区域表达方式不尽相同.结论 CD34在GG、PXA中阳性表达率高于DNT和对照组胶质瘤,对于诊断GG、PXA及与DNT、混合性星形-少突胶质细胞瘤、胶质母细胞瘤相鉴别具有一定的应用价值.     

即时荧光定量PCR微卫星分析技术检测少突胶质细胞肿瘤染色体1p/19q杂合性缺失

目的研究少突胶质细胞肿瘤染色体1p／19q杂合性缺失（LOH）情况。方法采用即时荧光定量PCR微卫星分析技术对28例少突胶质细胞肿瘤进行染色体1p／19qLOH检测。结果28例少突胶质细胞肿瘤染色体中有24例（85．7％）发生1pLOH;有18例（64．3％）发生19qLOH;有17例（60．7％）发生1p／19q联合性LOH;25例有1P或19qLOH。结论即时荧光定量PCR微卫星分析技术特异性高、方便快捷,可以用于石蜡包埋组织标本染色体杂合性缺失的检测。大多数少突胶质细胞肿瘤发生了1p／19qLOH。     

人脑胶质瘤血管内皮细胞生长因子受体表达的研究

目的　研究人脑胶质瘤血管内皮细胞生长因子受体 (Vascularendothelialgrowthfactorreceptors,VEGFR)的表达及意义 .方法　应用免疫组织化学技术 ,检测 5 2例手术切除的脑胶质细胞瘤组织中两种VEGFR(flt- 1和flk - 1)的表达 .结果　①胶质细胞瘤组织中有flt- 1和flk- 1的表达 ,主要表达于肿瘤血管内皮细胞 ,同时巨噬细胞的胞浆中也有表达 ;② 3组胶质细胞瘤中 ,VEGFR的表达率分别为 16 .0 %、5 8.8%、90 .0 % ,3组间有差异 (p <0 .0 5 ) ;③脑胶质细胞瘤中 ,flt- 1的表达与flk - 1的表达相关 (R =0 .993,p<0 .0 1) .结论　正常脑组织中无VEGFR表达 ,脑胶质细胞瘤中有VEGFR表达 ,主要表达于血管内皮细胞中 ,VEGF通过旁分泌途径刺激脑胶质细胞瘤的血管发生 ;VEGF的促血管发生作用既可通过血管内皮细胞的VEGFR直接产生 ,又可通过促进巨噬细胞的局灶浸润间接产生 ;VEGFR表达与脑胶质瘤恶性程度呈正相关     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

Simian virus 40 infection in humans and association with human diseases: results and hypotheses

Simian virus 40 (SV40) is a monkey virus that was introduced in the human population by contaminated poliovaccines, produced in SV40-infected monkey cells, between 1955 and 1963. Epidemiological evidence now suggests that SV40 may be contagiously transmitted in humans by horizontal infection, independent of the earlier administration of SV40-contaminated poliovaccines. This evidence includes detection of SV40 DNA sequences in human tissues and of SV40 antibodies in human sera, as well as rescue of infectious SV40 from a human tumor. Detection of SV40 DNA sequences in blood and sperm and of SV40 virions in sewage points to the hematic, sexual, and orofecal routes as means of virus transmission in humans. The site of latent infection in humans is not known, but the presence of SV40 in urine suggests the kidney as a possible site of latency, as it occurs in the natural monkey host. SV40 in humans is associated with inflammatory kidney diseases and with specific tumor types: mesothelioma, lymphoma, brain, and bone. These human tumors correspond to the neoplasms that are induced by SV40 experimental inoculation in rodents and by generation of transgenic mice with the SV40 early region gene directed by its own early promoter-enhancer. The mechanisms of SV40 tumorigenesis in humans are related to the properties of the two viral oncoproteins, the large T antigen (Tag) and the small t antigen (tag). Tag acts mainly by blocking the functions of p53 and RB tumor suppressor proteins, as well as by inducing chromosomal aberrations in the host cell. These chromosome alterations may hit genes important in oncogenesis and generate genetic instability in tumor cells. The clastogenic activity of Tag, which fixes the chromosome damage in the infected cells, may explain the low viral load in SV40-positive human tumors and the observation that Tag is expressed only in a fraction of tumor cells. "Hit and run" seems the most plausible mechanism to support this situation. The small tag, like large Tag, displays several functions, but its principal role in transformation is to bind the protein phosphatase PP2A. This leads to constitutive activation of the Wnt pathway, resulting in continuous cell proliferation. The possibility that SV40 is implicated as a cofactor in the etiology of some human tumors has stimulated the preparation of a vaccine against the large Tag. Such a vaccine may represent in the future a useful immunoprophylactic and immunotherapeutic intervention against human tumors associated with SV40.     

High throughput testing of the SV40 Large T antigen binding to cellular p53 identifies putative drugs for the treatment of SV40-related cancers

SV40 has been linked to some human malignancies, and the evidence that this virus plays a causative role in mesothelioma and brain tumors is mounting. The major SV40 oncoprotein is the Large tumor antigen (Tag). A key Tag transforming activity is connected to its capability to bind and inactivate cellular p53. In this study we developed an effective, high throughput, ELISA-based method to study Tag-p53 interaction in vitro. This assay allowed us to screen a chemical library and to identify a chemical inhibitor of the Tag binding to p53. We propose that our in vitro assay is a useful method to identify molecules that may be used as therapeutic agents for the treatment of SV40-related human cancers.     

SV40 Tag DNA sequences, present in a small proportion of human hepatocellular carcinomas, are associated with reduced survival

AIMS: To study the association between simian virus 40 (SV40) and human hepatocarcinogenesis. METHODS: Polymerase chain reaction (PCR) to detect SV40 large T antigen (Tag) DNA was performed on: 50 human hepatocellular carcinoma (HCCs) diagnosed between 1978 and 1989 (cohort A); 20 cases of alcoholic liver cirrhosis from the same period; and 20 HCCs diagnosed after 1997 (cohort B). PCR to detect SV40 regulatory sequence and SV40 Tag immunohistochemistry were performed on selected cases from cohorts A and B. Amplified products were directly sequenced. Immunohistochemistry for p53 and pRb and clinicopathological analyses were performed on selected cases from cohorts A and B. Complete survival data were collected for cohort A. RESULT: SV40 Tag DNA was found in five cohort A HCCs but not in alcoholic liver cirrhosis cases or cohort B HCCs. Neither SV40 regulatory sequence nor SV40 Tag protein were demonstrated in Tag DNA positive HCCs. No clinicopathological differences existed between Tag DNA positive and negative HCCs, but the presence of Tag DNA was associated with reduced disease specific survival. Relatively fewer Tag DNA positive than negative HCCs expressed p53, but loss of pRb expression was similar in the two groups. Patients with Tag DNA positive HCCs were unlikely to have received SV40 contaminated poliovirus vaccine. CONCLUSIONS: SV40 Tag DNA is present in a small proportion of historical HCCs and may contribute to their pathogenesis and influence their outcome. The source of the virus is uncertain and more recent HCCs show no evidence of SV40.     

Immunodetection of SV40 large T antigen in human central nervous system tumours

BACKGROUND/AIMS: DNA sequences from Simian virus 40 (SV40) have been previously isolated from various human tumours of the central nervous system (CNS). This study aimed to investigate a series of tumours of the CNS for the expression of the SV40 large T antigen (Tag), which is an oncogenic protein of the virus. METHODS: A French series of 82 CNS tumours was investigated for Tag expression using a monoclonal antibody and immunohistochemistry. A Tag positive hepatocellular carcinoma cell line from transgenic mice and a kidney biopsy from a patient infected by SV40 were used as positive controls. RESULTS: None of the tumours (20 ependymomas, 20 glioblastomas, 12 oligodendrogliomas, three plexus choroid adenomas, two plexus choroid carcinomas, 15 meningiomas, and 10 medulloblastomas) contained SV40 Tag positive cells. CONCLUSIONS: The lack of SV40 Tag in 82 CNS tumours of various types is at variance with previous studies from different countries, and suggests that the virus may not be an important factor in CNS tumorigenesis, at least in French cases.     

Immunohistochemical study of p53 protein in human and animal pituitary tumors

In many human cancers, p53 gene mutations are frequently occurring genetic abnormalities, which may be detected by immunohistochemical staining for p53 protein. In the present study, p53 immunoreactivity was investigated in formalin-fixed, paraffin-embedded tissues from human and animal pituitary tumors, using the avidin-biotin-peroxidase complex technique. No p53 was detected in 3 nontumorous human adenohypophyses or in 40 human pituitary tumors including 5 GH cell adenomas, 10 PRL cell adenomas, 2 mixed GH cell-PRL cell adenomas, 2 acidophil stem cell adenomas, 8 ACTH cell adenomas, 1 TSH cell adenoma, 1 FSH/LH cell adenoma, 5 null cell adenomas, 5 oncocytomas, and 1 plurihormonal adenoma. Twenty nontumorous and hyperplastic pituitaries of hGRH transgenic mice and 8 tumors in these transgenic animals were immunonegative for p53. All pituitary tumors found in AVP/SV40 transgenic mice contained p53 immunoreactivity in the nuclei, while the nontumorous adenohypophysis of one such transgenic mouse was negative. It can be concluded that p53 mutations are apparently not involved in the pathogenesis of human pituitary adenomas or of the pituitary tumors which develop in hGRH transgenic mice. However, pituitary tumors in AVP/ SV40 transgenic mice are accompanied by p53 expression.     

Absence of SV40 large T-antigen expression in human mesothelioma cell lines

Simian virus (SV) 40 and SV40-like DNA sequences have recently been detected in several types of human tumors, including malignant mesothelioma. However, the presence of SV40 DNA sequences is not sufficient to account for its possible role in tumor development because the viral proteins must be expressed and ultimately impair the function of relevant cell proteins, such as p53 and pRb. In this study we investigated SV40 large T antigen (SV40 Tag) protein expression in mesothelioma cell lines, established in our laboratory, by Western blotting, immunoprecipitation, and immunocytochemistry using Tag-specific mouse monoclonal antibodies (mAbs) Ab-1 (or Pab 419). By Western blotting of cell extracts, none of the mesothelioma cell lines expressed detectable amounts of SV40 Tag. However, we found that Ab-1 as well as Pab-101, another SV 40 Tag-specific mAb, may generate false-positive signals due to the fact that both antibody preparations are contaminated by a protein of similar size (90 kD) as SV40 Tag and react with the various secondary horseradish peroxidase- conjugated antimouse immunoglobulin Gs tested. The present study suggests that immunodetection of SV40 Tag protein may be puzzling because this contaminating Taglike protein may bind to particular cell structures, thereby generating false-positive signals.     

Presence and expression of the simian virus-40 genome in human giant cell tumors of bone

SV40 DNA sequences have been found in human tumors, such as mesotheliomas, ependymomas, and bone tumors, suggesting that SV40 may be involved in their etiology. The FOS oncogene could play an important role in bone development because SV40 is able to induce FOS in cell culture. In this study, the presence of SV40 sequences, large T antigen (Tag), and FOS protein expression were investigated in 120 giant cell tumors (GCTs), moderately benign bone tumors that in some cases can progress to a malignant phenotype. Polymerase chain reaction (PCR), using primers that amplify the RB1 pocket binding domain and the intron of Tag, was used to analyze GCT for the presence of SV40 DNA. Tag and FOS protein expression was evaluated by immunohistochemistry. SV40 sequences were found in 30/107 GCTs, and of these, 22/30 samples expressed Tag protein (73%) and 15/30 overexpressed the FOS oncogene (50%). FOS was undetectable in 77 SV40-negative GCTs. Sequence analysis of the amplified DNAs confirmed that the amplified sequences corresponded to SV40 DNA. The correlation between FOS overexpression and SV40-positive GCTs was highly statistically significant (P < 0.001). These results show that SV40 DNA sequences and SV40 Tag are present in GCTs and might induce FOS activity. These data suggest that SV40 might play a role in the development and progression of some GCTs.     

SV40 large T antigen-specific human T cell memory responses

The continued presence of simian virus 40 (SV40), a monkey polyomavirus, in man is confirmed by the regular detection of SV40-specific antibodies in 5-10% of children who are unlikely to have received contaminated polio-vaccines. The aim of our experiments was to find cellular immunological evidence of SV40 infection in humans by testing memory T cell responses to SV40 large T antigen (Tag). As there is some indication that the virus may be present in malignant pleural mesothelioma (MPM) cells, we analyzed T cell responses in MPM patients and in healthy donors. The frequencies of responding T cells to overlapping Tag peptides were tested by cytokine flow cytometry. CD8+ T cells from 4 of 32 MPM patients responded (above twofold of control) to SV40 Tag peptides, while no positive responses were detected in 12 healthy donors. Within SV40 Tag we identified three 15 amino acid-long immunogenic sequences and one 9 amino acid-long T cell epitope (p138) (138FPSELLSFL146), the latter including a HLA-B7-restriction motif. T cell responses to p138 were SV40-specific as T cells stimulated with p138 did not cross-react with the corresponding sequences of Tag of human polyomaviruses BKV and JCV. Similarly, the relevant BKV and JCV Tag peptides did not generate T cell responses against SV40 TAg p138. Peptide-stimulated T cells also killed SV40 Tag-transfected target cells. This article demonstrates the presence, and provides a detailed analysis, of SV40-specific T cell memory in man.     

Mutations of p53 gene and SV40 sequences in asbestos associated and non-asbestos-associated mesotheliomas.

AIM: To examine mesotheliomas for a possible relation between p53 immunostaining, p53 gene mutation, simian virus 40 (SV40), and asbestos exposure. METHODS: Paraffin sections from 11 mesotheliomas were used for p53 immunostaining and also to extract DNA. This was analysed for the presence of mutations in exons 5 to 8 of the p53 gene using a "cold" single strand conformational polymorphism method, together with sequencing. The DNA from the paraffin sections was also used to search for SV40 sequences. A 105 base pair segment at the 3' of the SV40 large T antigen (Tag) was targeted and any PCR amplification products were sequenced to confirm that they were of SV40 origin. EDAX electron microscopic differential mineral fibre counts were performed on dried lung tissue at a specialist referral centre. RESULTS: The fibre counts showed that seven of the mesotheliomas were associated with abnormally high asbestos exposure. Of these, two showed p53 immunostaining, none showed p53 gene mutation, and five showed SV40. Of the four other mesotheliomas, three showed p53 immunostaining, one showed a (silent) p53 mutation, and none showed SV40. The difference in frequency of SV40 detection was significant at the p < 0.05 level. CONCLUSIONS: Immunostaining for the p53 gene was relatively common but p53 mutations were rare in this series. SV40 virus sequence was detected in five of seven asbestos associated mesotheliomas but in none of the non-asbestos-associated mesotheliomas. This suggests there may be a synergistic interaction between asbestos and SV40 in human mesotheliomas. A study with a larger number of cases is needed to investigate these observations further.