Evaluation of simian virus-40 as a biological prognostic factor in Egyptian patients with malignant pleural mesothelioma

The association between simian virus (SV40) and malignant pleural mesothelioma (MPM) suggests an etiological role for SV40. However, exact pathogenetic mechanisms and possible prognostic value are not clear. The purpose of the present paper was to investigate 40 Egyptian MPM patients for the presence of SV40 DNA, altered Rb expression and p53 gene status using immunohistochemistry and molecular techniques. The relation between SV40, asbestos exposure, Rb, p53 and their contribution to the overall survival (OS) were also assessed. SV40 DNA was detected in 20/40 patients and asbestos exposure in 31 patients; 18 of them were SV40 positive. Altered p53 and Rb expression were detected in 57.5% and 52.5%, respectively, with no p53 mutation. Univariate analysis showed a significant correlation between OS and stage (P = 0.03), performance status (P = 0.04), p53 overexpression (P = 0.05), asbestos exposure (P = 0.002) and SV40 (P = 0.001). Multivariate analysis showed that when SV40 and asbestos exposure were considered together, only combined positivity of both was an independent prognostic factor affecting the OS (P = 0.001). SV40 and asbestos exposure are common in Egyptian MPM, denoting a possible etiological role and a synergistic effect for both agents. Combined positivity for SV40 and asbestos exposure is an independent prognostic factor in MPM, having a detrimental effect on OS.     

SV40-like DNA sequences in pleural mesothelioma,bronchopulmonary carcinoma,and non-malignant pulmonary diseases

Pleural and pulmonary malignancies are usually associated with well-known carcinogen exposure. Recently, the presence of simian virus 40 (SV40)-like DNA sequences has been detected in brain and bone-related human cancers and in pleural mesothelioma. In order to determine whether SV40-like DNA sequences are also present in bronchopulmonary carcinoma and non-malignant lung samples, 125 frozen pleural and pulmonary samples (including 21 mesotheliomas, 63 bronchopulmonary carcinomas, 8 other tumours, and 33 non-malignant samples) and 38 additional samples distant from tumours were studied for the occurrence of SV40-like DNA sequences by polymerase chain reaction (PCR) amplification followed by hybridization with specific probes. Sequences related to SV40 large T antigen (Tag) were present in 28·6 per cent of bronchopulmonary carcinomas, 47·6 per cent of mesotheliomas, and 16·0 per cent of cases with non-neoplastic pleural and pulmonary disease. No statistically significant difference in the occurrence of these DNA sequences was found between malignant mesothelioma and bronchopulmonary carcinoma, but a significantly higher number of mesothelioma cases exhibited SV40-like DNA sequences in comparison with cases of non-malignant pleural or pulmonary disease (P<0·04). Among cases positive for SV40-like DNA sequences, a history of asbestos exposure was found in 3 out of 12 bronchopulmonary carcinomas and 8 out of 10 mesotheliomas. Immunohistochemistry using monoclonal antibodies directed against Tag did not demonstrate nuclear staining. The DNA sequences were not related to BK virus sequences, but three samples were positive with probes hybridizing with JC virus DNA sequences. In conclusion, this study demonstrates the presence of SV40-like DNA sequences in pulmonary neoplasms and in non-malignant lung tissues. It appears that the presence of SV40-like DNA is not unique to cancer. © 1998 John Wiley & Sons, Ltd.     

Absence of SV-40 large T antigen (Tag) in malignant mesothelioma effusions: an immunocytochemical study

Simian Virus 40 (SV 40) was recently implicated in the pathogenesis of malignant mesothelioma. The oncogenic capacity of SV-40 is a function of a nuclear protein, the large T antigen (Tag). SV-40 Tag DNA sequences are detected by the polymerase chain reaction in 40-80% of malignant mesothelial proliferations. However, the role of immunohistochemistry (IHC) in demonstrating the nuclear localization of Tag is controversial. We sought to determine the clinical utility of SV-40 Tag IHC in pleural effusion cytology as an ancillary tool in the cytologic diagnosis of malignant mesothelioma (MM). Formalin-fixed, paraffin-embedded cell block sections from 100 pleural effusions (32 MMs, 25 benign reactive, 43 metastatic adenocarcinomas) were immunostained for the SV-40 anti-Tag, using two primary monoclonal SV-40 Tag antibodies: clone Pab 416 and clone Pab 101. Despite strong and consistent immunoreactivity in positive controls, no nuclear immunostaining was observed in any case. We believe the small sample size in cytology cell block sections, the low viral copy number in infected cells, and the effect of formalin fixation may have resulted in absence of immunoreactivity. The role of SV-40 Tag IHC in diagnostic cytopathology remains unclear unless further studies reliably show its detection.     

Simian virus 40 mutants with amino-acid substitutions near the amino terminus of large T antigen

A series of amino-acid substitution mutants has been made with changes in the region of simian virus 40 large tumor antigen (T antigen) that is shared with the small tumor antigen (t antigen). Both single and multiple amino-acid replacements were obtained using the heteroduplex deletion loop method and sodium bisulfite as the mutagen. The mutants could be divided into five phenotypic classes on the basis of their biological properties: a) mutants whose changes did not affect their ability to propagate on permissive monkey cells, nor to transform nonpermissive rodent cells; b) mutants that were not viable, replicated their DNA to 5% or less of wild type, but were positive for transformation; c) mutants that were not viable, replicated their DNA to 5% or less of wild type, and were defective for transformation; and d) mutants that completely lost all three activities coordinately. In addition, one mutant with changes in this region, 5002, replicated its DNA to about 50% of wild type, had an impaired transformation activity, and produced virions at a level of about 4% that of wild type.     

Absence of simian virus 40 DNA sequences in primary central nervous system lymphoma in HIV-negative patients

Simian virus 40 (SV40) is known to induce primary brain tumors and lymphomas in animal models. Recently, it was also associated with the pathogenesis of human non-Hodgkins lymphomas. In the present study, we investigated primary central nervous system lymphomas (PCNSL), a defined subgroup of diffuse large B-cell lymphoma confined to the central nervous system, for the presence of SV40 DNA. Frozen tissue samples of 23 PCNSL derived from human immunodeficiency virus-negative patients were analyzed by two different, fully nested polymerase chain reaction protocols. SV40 DNA sequences could not be detected in any of these samples. Thus, SV40 can be added to the list of viruses that have already been excluded as pathogenetically relevant cofactors in PCNSL.     

Localized malignant mesothelioma of the pleura

We describe a case of malignant pleural mesothelioma appearing as a solitary pleural tumor in a 56-year-old Japanese man with no history of exposure to asbestos. A chest radiograph revealed an isolated extrapulmonary mass in the left hemithorax. The patient underwent tumor resection, but the tumor later recurred on the contralateral pleura. The patient developed cerebral metastases and died 16 months after the initial surgery. The resected tumor was sessile with broad-based pleural attachment. Microscopically, the tumor was composed of interlacing fascicles of plump spindle cells intermixed with few polygonal cells. Most of the tumor cells showed positive immunoreactivity for cytokeratins (AE1 and AE3) and vimentin. Many of the tumor cells were positive for epithelial membrane antigen, and a few were positive for desmin. In contrast, the tumor cells were consistently negative for carcinoembryonic antigen, epithelial antigen BerEP4, calretinin, S-100 protein, neuron-specific enolase, muscle actin antigen HHF35, alpha-smooth muscle actin antigen and CD34. Ultrastructurally, the tumor cells had diffusely distributed cytoplasmic intermediate filaments, desmosome-like junctions, and a few microvilli. Some tumor cells contained cytoplasmic tonofilaments. Immunohistochemical and ultrastructural findings supported the mesothelial nature of the tumor, and led us to diagnose this tumor as a sarcomatoid localized malignant mesothelioma.     

Localized malignant peritoneal mesothelioma containing rhabdoid cells

A case Is presented of localized malignant peritoneal mesothelioma appearing as a liver neoplasm. The patient underwent tumor resection but developed a recurrent growth and died 10 months after the Initial surgery. The primary tumor showed sarcomatous features with rhabdoid cells. Examination revealed the presence of hyaluronic acid, co-Immunoreactivlty for cytokeratln epithelial membrane antigen and vlmentln, cellular contacts with small desmosomes, and intracytoplasmic lumina. These findings supported the mesothelial nature of this tumor. The recurrent tumor was composed of predominantly tubulopaplllary proliferation. It was concluded that the present tumor was a localized malignant mesothelioma of a blphasic type showing a predominantly sarcomatous component in the primary tumor.     

恶性间皮瘤的肿瘤相关成纤维细胞的特点

目的:通过观察恶性间皮瘤的肿瘤相关成纤维细胞(tumor-associated fibroblasts,TAF)的免疫表型特点,探讨其在诊断治疗中的意义.方法:收集恶性间皮瘤10例,食管癌、乳腺癌、结肠癌标本各10例,观察这些肿瘤TAF的CK,CK19,Calretinin,HBME-1,Vimentin,Sny,S-100等表达情况.结果:10例恶性间皮瘤、食管鳞状细胞癌、乳腺浸润性导管癌、结肠腺癌的TAF都阳性表达Vimentin,均灶状表达Syn,S-100.10例恶性间皮瘤的TAF阳性表达CK,CK19,Calretinin,弱阳性表达HBME-1;10例食管鳞状细胞癌、乳腺浸润性导管癌、结肠腺癌的TAFs均局灶弱阳性表达CK,Calretinin,不表达HMBE-1及CK19;恶性间皮瘤组的TAF表达Calretinin,CK19,CK,HBME-1的积分光密度值(integrated optical density,IOD)显高于其余3组(P＜0.05).结论:恶性间皮瘤的TrAF与一般常见的上皮性肿瘤的TAF免疫表型既有共性又有不同,深入了解其免疫表型及分子生物学特性对研究恶性间皮瘤的诊断及治疗有重大意义.     

SV40TAg真核表达载体的设计与构建

目的 设计并构建SV40TAg真核表达载体。方法 采用重叠延伸拼接法从pUC19-SV40载体中克隆切除了内含子的SV40LT基因全长，在其5’端连上loxP位点，EcoR I、BamH I双酶切，同时采用重叠延伸拼接法从pEGFP-N1真核表达载体中克隆EGFP基因全长，并在3’端连上loxP位点，两个酶切产物连接后定向克隆至pEGFP-N1真核表达载体，DNA序列分析鉴定重组质粒。结果 SV40LT基因和两个loxP位点成功克隆至pEGFP-N1真核表达载体中。结论 本实验构建的SV40LT重组质粒为利用SV40T抗原进行黑素细胞发育、分化，黑素生成以及黑素瘤发生等研究提供了新的分子工具。     

The carboxyl-terminal domain of large T antigen rescues SV40 host range activity in trans independent of acetylation

The host range activity of SV40 has been described as the inability of mutant viruses with deletions in the C terminal region of large T Ag to replicate in certain types of African green monkey kidney cells. We constructed new mutant viruses expressing truncated T Ag proteins and found that these mutant viruses exhibited the host range phenotype. The host range phenotype was independent of acetylation of T Ag at lysine 697. Co-expression of the C terminal domain of T Ag (aa 627-708) in trans increased both T Ag and VP1 mRNA as well as protein levels for host range mutant viruses in the restrictive cell type. In addition, the T Ag 627-708 fragment promoted the productive lytic infection of host range mutant viruses in the nonpermissive cell type. The carboxyl-terminal region of T Ag contains a biological function essential for the SV40 viral life cycle.     

Immunohistochemical phenotype of malignant mesothelioma: predictive value of CA125 and HBME-1 expression

Histological diagnosis of malignant mesothelioma and differentiation from adenocarcinoma is often difficult. Definitive pathological confirmation of malignant mesothelioma requires demonstration of an appropriate immunohistochemical phenotype. Selection of an optimum panel of immunohistochemical antibodies for the reliable identification of malignant mesothelioma is hindered by the absence of a specific immunohistochemical label for mesothelioma cells. Recently, we have found that the ovarian carcinoma cell antibody CA125 labels malignant mesothelioma cells, and the antibody HBME-1 has been developed as a sensitive mesothelial cell marker. We have compared the immunohistochemical staining patterns achieved with CA125 and HBME-1 to those obtained using a panel of eight further antibodies in 17 malignant mesotheliomas and 14 primary and secondary adenocarcinomas within lung and pleura. CA125 labelled malignant mesothelioma cells in 15 of 17 cases (88%), and adenocarcinoma cells in seven of 14 cases (50%). HBME-1 labelled mesothelioma cells in all 17 cases (100%) but also labelled adenocarcinoma cells in 10 of 14 cases (71%). BerEP4 positively labelled one malignant mesothelioma but was negative in the remaining 16 cases and positively labelled nine of 14 adenocarcinomas (64%). Monoclonal anti-CEA, AUA-1, CA19.9 and LeuM1 labelled no malignant mesotheliomas and were positive in 10 (71%), nine (64%), eight (57%) and six (43%) of 14 cases of adenocarcinoma, respectively. Diastase-PAS staining detected neutral mucin in none of the malignant mesotheliomas but in 10 (71%) of the 14 adenocarcinomas. We conclude that CA125 and HBME-1 do not label mesothelial cells with sufficient specificity to be useful for differentiating malignant mesothelioma from adenocarcinoma, although negative staining with HBME-1 makes a diagnosis of malignant mesothelioma unlikely. As there remains an absence of a specific positive mesothelial cell marker this distinction is still most reliably made using a panel of antibodies including at least two of the following: anti-CEA, AUA-1, BerEP4, LeuM1 and CA19.9, in combination with histochemical assessment of neutral mucin production.     

The diagnostic utility of D2-40 for malignant mesothelioma versus pulmonary carcinoma with pleural involvement

Differentiating malignant mesothelioma (MM) from pulmonary carcinoma in pleural fluid cytology can be challenging. Recent studies have suggested that D2-40, a novel lymphatic marker, may be a useful marker for mesothelial differentiation in surgical specimens. However, there are no available data regarding its utility in effusion cytology specimens. We investigated the utility of D2-40 in pleural fluid cytology in differentiating MM from pulmonary carcinomas. Twenty cases of pleural effusion smears of surgically confirmed MM with their corresponding cell blocks were retrieved from the database of the hospital computer system. We also included 10 cases of metastatic pulmonary adenocarcinoma (PA) and 10 cases metastatic pulmonary squamous cell carcinoma (PSCC) involving the pleural fluid. Cell blocks were formalin-fixed, paraffin embedded, and immunostained for TTF1, p63, calretinin, CK5/6, WT-1, and D2-40. Cases were scored as negative (<5% positivity) or positive (>5% moderate/strong positivity). The positive rates for TTF1, p63, calretinin, CK5/6, WT-1, and D2-40 were as follows: MM (0/20), (0/20), (17/20), (18/20), (19/20), (17/20), for PA (8/10), (0/10), (3/10), (0/10), (0/10), (0/10), and for PSCC (1/10), (10/10), (6/10), (10/10), (0/15), (0/10). The staining pattern for D2-40 was characterized by thick membranous staining. Diffuse cytoplasmic staining by D2-40 was seen in 2 cases of pulmonary carcinoma, counted as negative. Our study showed that in differentiating MM from PA, CK5/6, WT-1, and D2-40 have high specificity and sensitivity for MM. Although calretinin is a sensitive IHC marker for MM, it is not specific since it stained 30% of PA. Conversely, to differentiate between MM and PSCC, p63 and WT-1 are the best available markers. We recommend a panel of CK5/6, p63, D2-40, and WT-1 to differentiate MM from pulmonary carcinomas in effusion cytology specimens.     

猿猴病毒40 T抗原转化的人脐静脉内皮细胞系PUMC-HUVEC-T1的建立

目的 建立猿猴病毒40（SV40）T抗原转化的人脐静脉内皮细胞（HVUEC）模型,为内皮研究提供可利用资源。方法 分离人脐静脉内皮细胞,原代培养。感染含有SV40大T、小T抗原的慢病毒,连续传代培养。对感染后的HUVEC,RT-PCR检测大T的表达,免疫细胞化学检测vWF、CD31、CD34的表达及结合凝集素能力,透射电镜观察内皮细胞的超微结构,Matrigel检测管状成型,进行染色体核型分析,皮下接种BABL/c-nu裸鼠检测致瘤性,PCR法进行种属鉴定及支原体检测,短串联重复序列（STR）检测鉴定细胞身份。结果 转化后的人脐静脉内皮细胞命名为PUMC-HUVEC-T1,扁平多角状,汇合时典型铺路石排列,体外传代40代以上（1∶3～4）;细胞中有SV40LT mRNA的表达;vWF、CD31、CD34表达均阳性,可结合荆豆凝集素-1（UEA-1）;电镜可见WP小体;不同代数细胞核型正常稳定,裸鼠体内接种不成瘤。PUMC-HUVEC-T1种属鉴定为人源性,STR结果与原代HUVEC一致,无支原体的污染,国家实验细胞资源共享平台收藏。结论 建立了易获得、背景清楚、质量可靠的SV40 T抗原转化的HUVEC细胞系PUMC-HUVEC-T1。     

An autopsy case of a malignant pericardial mesothelioma in a Japanese young man

An autopsy case of a malignant pericardial mesothelioma in a 27-year-old man with no history of exposure to asbestos is reported. He was admitted for heart failure due to pericardial effusion of unknown origin and surgically drained, but later died. The diagnosis of a malignant pericardial mesothelioma was made on the basis of histologic, immunohistochemical and ultrastructural findings. The tumor was located on the pericardium, but autopsy revealed that it had spread extensively in the mediastinum and the lungs. Microscopically, the tumor cells were epithelial like and contained histochemically demonstrable glycogen and hyaluronic acid. Immunohistochemical studies of the tumor demonstrated positive immunoreactivity for cytokeratin 19, muscle actin HHF35, epithelial membrane antigen, CA125, p53 and p21WAF1/CIP1 whereas the tumor was negative for cytokeratins 10 and 17, carcinoembryonic antigen, vimentin, epithelial antigen BerEP4, S-100, c-erbB2 and bcl-2. A high MIB-1 labeling index was noted. Under the electron microscope the tumor cells exhibited long, thin villi. The operation and autopsy findings thus revealed this to be a very rare case of malignant pericardial mesothelioma in a young man.     

Well‐differentiated papillary mesothelioma,possibly giving rise to diffuse malignant mesothelioma: A case report

Well‐differentiated papillary mesothelioma (WDPM) is a distinct subtype of mesothelial tumor from diffuse malignant mesothelioma (DMM), with an uncertain malignant potential. The relationship between WDPM and DMM, with regard to the ability of the former to develop into the latter, is also unknown. A 58‐year‐old woman, diagnosed with a rectal carcinoid tumor, underwent removal of the lymph nodes via the abdomen in 2004. A large number of white miliary nodules were identified on the mesentery and peritoneum, which were histologically diagnosed as WDPM. No further therapy was administered, but the patient was followed‐up using imaging methods. Seven years later, an abdominal wall mass was discovered using positron emission tomography‐computed tomography, and a laparotomy biopsy was performed. DMM was diagnosed, because mesothelioma with extended invasion had been histologically identified. Mesothelioma similar to papillary proliferation was present on the outer layer of the peritoneum, and an infiltrating lesion with continuous restiform or solid‐like structures was noted. WDPM was believed to have undergone malignant transformation. Compared to DMM, WDPM has a good prognosis and is considered a benign or borderline neoplasm. Our findings suggest that WDPM does have malignant potential, however, because histological findings indicated a malignant transformation of WDPM to DMM.     

Heparanase and basic fibroblast growth factor are co-expressed in malignant mesothelioma

Heparanase is an endoglycosidase that degrades heparan sulfate (HS) in the extracellular matrix (ECM) and cell surfaces, and fulfills a significant role in cancer metastasis and angiogenesis. We evaluated the expression of heparanase and its possible association with the expression of angiogenic molecules in malignant mesothelioma (MM), and analyzed whether expression of these proteins is site-related (pleural vs peritoneal MM, solid lesions vs effusions). Sections from 80 MM (56 biopsies, 24 effusions) were analyzed for heparanase protein expression using immunohistochemistry (IHC). Sixty MM were of pleural origin, and 20 were peritoneal. Effusion specimens consisted of 6 peritoneal and 18 pleural effusions, while biopsies consisted of 14 peritoneal and 42 pleural lesions. Fifty-four specimens were additionally evaluated for expression of basic fibroblast growth factor (bFGF), interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) proteins using IHC. Microvessel density (MVD) was studied in 28 biopsies using an anti-CD31 antibody. mRNA expression of heparanase (HPSE-1), VEGF and the VEGF receptor KDR was analyzed in 23 effusions using RT-PCR. Heparanase protein expression was seen in 69/80 (86%) tumors. Of these, 35 showed combined membrane and cytoplasmic expression, 30 cytoplasmic expression, and four exclusively membrane expression. Both total (P= 0.001) and cytoplasmic (P = 0.002) expression was significantly higher in solid tumors compared to effusions. Protein expression of VEGF, IL-8 and bFGF was seen in 21/54 (39%), 22/54 (41%) and 44/54 (81%) specimens, respectively. Protein expression of bFGF was significantly higher in solid tumors (P 0.001) and correlated with heparanase expression (P = 0.005). HPSE-1 and VEGF mRNA expression was detected in all 23 effusions using RT-PCR, while KDR mRNA was found in 12/23 MM. KDR mRNA expression correlated with that of both HPSE-1 (P = 0.005) and VEGF (P = 0.001). Our results document frequent expression of heparanase in MM, in agreement with the biological aggressiveness of this tumor. The co-expression of heparanase with bFGF is in agreement with the role of the former in releasing bFGF from the ECM. The concomitant reduction in protein expression of both molecules in effusions as compared to solid tumors, supports the hypothesis of a reduced need for pro-angiogenic stimuli in effusions, and may aid in defining tumor progression in this setting.