Overexpression of Ets-1 proto-oncogene in latent and clinical prostatic carcinomas

AIMS: The high incidence of clinically diagnosed prostatic cancer is exceeded by the frequency of tumours detected at autopsy. The Ets-1 proto-oncogene is expressed by a variety of malignant and normal tissues. Therefore, in this study, expression of Ets-1 protein was investigated in 'latent' prostatic cancer detected at autopsy, compared with benign prostatic hyperplasia, normal prostatic tissues and clinical prostatic cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed Ets-1 expression in 95 prostatic specimens including 19 cases of latent prostatic carcinoma (LPC) and 55 cases of clinical prostatic carcinoma (CPC), 11 cases of benign prostatic hyperplasia (BPH) and 10 cases of normal prostate (NP). Differences in the incidence of LPC and CPC suggest different courses for the biological progression of prostatic cancer. There was a significant difference in the degree of Ets-1 expression in CPC and LPC (P < 0.05). Ets-1 was not expressed in BPH and NP, but in malignant cases (57 of 74; 77.0%) commonly demonstrated immunoreactivity in the tumour cells. In our study the expression of Ets-1 between benign and malignant, and well, moderately and poorly differentiated adenocarcinomas of prostatic cancer showed significant differences. The presence of Ets-1 mRNA was confirmed by in-situ hybridization in human prostatic tissues. CONCLUSION: Our results suggest that Ets-1 might play an important role in carcinogenesis and/or the progression of human prostatic carcinomas.     

Expression of autocrine motility factor mRNA is a poor prognostic factor in high-grade astrocytoma

It has been reported that tumor infiltration is correlated with the expression of autocrine motility factor (AMF) and its receptor 78 kDa glycoprotein (gp78). The purpose of the present study was to detect AMF and gp78 mRNA expression levels and their localization in high-grade astrocytomas (glioblastoma and anaplastic astrocytoma) and to determine whether AMF and gp78 are important prognostic factors. A total of 32 formalin-fixed and paraffin-embedded glioblastomas and 23 formalin-fixed and paraffin-embedded anaplastic astrocytomas was used. The expressions of AMF and gp78 mRNA were detected using the highly sensitive in situ hybridization method. The expression of AMF mRNA was detected in 27 of 32 glioblastomas (84.4%) and 11 of 23 anaplastic astrocytomas (47.8%). The positivity of AMF mRNA was significantly higher in glioblastomas than in anaplastic astrocytomas (P = 0.0094), but gp78 mRNA was detected in most cases and no statistical significance was observed. The overall survival of patients with AMF expression was significantly shorter than patients without AMF expression (P = 0.0175). In anaplastic astrocytomas, the overall survival of patients with AMF expression was also significantly shorter than in patients without AMF expression (P = 0.0058). This study demonstrated that AMF is a poor prognostic factor in high-grade astrocytomas.     

星形细胞瘤p16与Rb蛋白的表达及其相关性研究

目的检测ｐ１６与Ｒｂ蛋白在原发性星形细胞瘤中的存在状况，以探讨不同病理类型星形细胞瘤中ｐ１６与Ｒｂ蛋白表达及其相关性。方法使用抗ｐ１６及Ｒｂ蛋白抗体对１０２例星形细胞瘤手术标本进行免疫细胞化学检测。结果低度恶性星形细胞瘤（ＷＨＯⅠ～Ⅱ级）中ｐ１６及Ｒｂ蛋白均为阳性表达，在高度恶性星形细胞瘤（ＷＨＯⅢ～Ⅳ级）中其阳性表达分别为４８．１％（２６／５４）和５７．４％（３１／５４）。在３１例Ｒｂ蛋白阳性标本中，有２４例（７７．４％）显示ｐ１６蛋白表达缺失或低表达，而在２３例Ｒｂ蛋白阴性标本中却有１９例（８２．６％）显示ｐ１６蛋白阳性或强阳性。结论（１）ｐ１６及Ｒｂ蛋白参与星形细胞瘤细胞增殖过程并影响其细胞分化；（２）ｐ１６与Ｒｂ蛋白之间阳性表达的相互抑制，可能是高度恶性星形细胞瘤的标志之一。     

Coexpression of hepatocyte growth factor and receptor (Met) in human breast carcinoma.

Expression of hepatocyte growth factor (HGF) and HGF receptor (HGFR, product of the met proto-oncogene) mRNA were examined by nonisotopic in situ hybridization in a spectrum of benign and malignant human breast tissues. mRNA for both HGFR and HGF was detected in benign ductal epithelium. Epithelial expression of HGF mRNA was particularly intense in regions of ductal epithelial hyperplasia. Positive expression of HGF (but not HGFR) mRNA was also found in adipocytes, endothelial cells, and to varying degrees in stromal fibroblasts. In 12 of 12 cases of ductal carcinoma in situ and infiltrating ductal carcinoma, carcinoma cells showed a heterogeneous pattern of expression for both HGFR and HGF mRNA. In infiltrating ductal carcinomas, intense expression of HGFR mRNA was not restricted to ductular structures but as also seen in non-duct-forming carcinoma cells. The same zones of the tumors (most commonly at the advancing margins) that expressed strongly HGFR mRNA often were also strongly positive for HGF mRNA, suggesting a possible autocrine effect. The expression pattern of HGFR protein in 25 cases including the same series of tissues used for in situ hybridization analysis was similar to that of HGFR mRNA, as determined by an immunoperoxidase technique. The finding that HGFR is expressed by both benign and malignant epithelium, and its not restricted to duct-forming structures, suggests that, although the potential for HGF/HGFR binding is maintained in malignancy, the response to ligand binding at the level of the receptor or the cellular response to receptor activation may change at some point during progression.     

Expression of matrix metalloproteinases and their inhibitors in human brain tumors

Sixty human brain tumors, classified according to the New World Health Organization (WHO) classification including, grade I schwannomas, meningiomas and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas, grade IV glioblastomas, grade III anaplastic oligodendrogliomas and grade IV glioblastomas and lung and melanoma metastases were analyzed for the expression of three matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs) and for MMP activity. Some correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. MMP-9 levels were found to be significantly higher in grade III anaplastic astrocytomas and anaplastic oligodendrogliomas than those in grade I schwannomas and meningiomas. Anaplastic astrocytomas and Grade IV glioblastomas expressed significantly higher levels MMP-12 than grade I meningiomas. All sixty tumors showed a similar pattern of activity in zymography, proMMP-9 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were especially low in tumors of grade II and grade III but significantly higher in tumors of grade I, particularly in schwannomas. Taken together, these data suggest that: 1) a balance between MMPs and TIMPs has an important role to play in human brain tumors; 2) TIMP expression may be valuable markers for tumor malignancy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Telomere-mediated genomic instability and the clinico-pathological parameters in breast cancer

A study was undertaken to correlate telomere dysfunction and genomic instability with the histopathological grades and the estrogen and progesterone receptor status in breast cancer. Sixty-one archived breast tissues (38 cancer tissues and 23 paired normal tissues) were used in the study. The breast tumor tissues showed significantly shorter telomeres (7.7 kb) compared with the paired adjacent tissues (9.0 kb) by Southern blot analysis. Moreover, telomere shortening was more significant in Grade III tumors than in the Grade II tumors (P = 0.05). Quantitative fluorescence in situ hybridization on paraffin tissue sections revealed a similar trend in telomere shortening. Telomere attrition was associated with telomere dysfunction as revealed by the presence of significantly higher anaphase bridges in tumor cells which was tumor grade dependent. Furthermore, estrogen receptive negative tumors displayed higher anaphase and internuclear bridges. Selected samples from each grade showed greater genomic imbalances in the higher grades than the lower grade tumors as detected by array-comparative genomic hybridization. Telomerase activity was found to be higher in the higher grades (Grade II and III) compared with the lower grade (Grade I). The average mRNA expression of TRF1 and POT1 was lower in the tumor tissues than in the normal tissues. Tankyrase 1 mRNA expression showed a grade-dependent increase in tumor tissues and its expression was also high in estrogen and progesterone negative tumors. The data support the notion that telomere dysfunction might be of value as a marker of aggressiveness of the tumors in breast cancer patients.     

人脑星形细胞瘤纤溶酶原激活抑制因子1基因表达研究

目的研究人脑星形细胞瘤纤溶酶原激活抑制因子１（ＰＡＩ１）基因表达及其临床意义。方法采用Ｎｏｒｔｈｅｒｎ杂交和免疫组化ＡＢＣ方法检测３６例人脑星形细胞瘤ＰＡＩ１ｍＲＮＡ和蛋白表达，分析其与临床病理因素之间的关系。结果所有星形细胞瘤组织均可表达３．０ｋｂ和２．２ｋｂ的ＰＡＩ１ｍＲＮＡ转录物；高分级星形细胞瘤ＰＡＩ１ｍＲＮＡ表达水平显著高于低分级星形细胞瘤（Ｐ＜００１）；正常脑组织未检测出ＰＡＩ１ｍＲＮＡ表达。ＰＡＩ１ｍＲＮＡ表达水平与星形细胞瘤的坏死（ｒ＝０．５１，Ｐ＜０．０１）、微血管数（ｒ＝０．３３，Ｐ＜０．０１）及脑水肿（ｒ＝０．２７，Ｐ＜０．０１）呈显著正相关，与患者性别、年龄及瘤体大小无显著相关性。免疫组化染色显示，ＰＡＩ１蛋白主要分布在高分级星形细胞瘤的瘤细胞和内皮细胞，尤以血管增殖部位和坏死灶周围较为显著，低分级星形细胞瘤呈低水平表达。结论ＰＡＩ１基因表达与人脑星形细胞瘤的分级、坏死、血管生成及脑水肿密切相关，可作为星形细胞瘤恶性程度的分子标记。     

Neural cell adhesion molecule L1 in gliomas: correlation with TGF-beta and p53.

AIMS: To assess immunohistochemically whether the neural cell adhesion molecule L1, which is a member of the immunoglobulin superfamily and has been shown recently to be a stimulating factor for glioma migration, is expressed in glioma tissues, and to investigate factors that can regulate this expression. METHODS: Twenty seven glioma tissue specimens including 13 glioblastomas, seven anaplastic astrocytomas, and seven astrocytomas were examined. Immunohistochemical analyses of L1, p53, and transforming growth cell factor beta (TGF-beta) were performed on each tumour using both polyclonal and monoclonal antibodies. RESULTS: Nine (33%) specimens (six glioblastomas and three anaplastic astrocytomas) had L1 positive immunostaining. p53 positive staining was detected in 10 (43%) of 23 glioma specimens (seven glioblastomas and three anaplastic astrocytomas). TGF-beta positive immunostaining was observed in 12 (52%) of the 23 glioma specimens (six glioblastomas, four anaplastic astrocytomas, and two astrocytomas). There was a statistical correlation between both p53 and L1 expression and TGF-beta and L1 expression. No such correlation was found between p53 and TGF-beta expression. CONCLUSIONS: These results suggest that mutation of the p53 gene or expression of TGF-beta may upregulate the expression of the L1 gene, thus resulting in high grade migration of glioma cells.     

Up-regulation of urokinase and urokinase receptor genes in malignant astrocytoma.

To understand the role of urokinase (u-PA) and the urokinase receptor (u-PAR) in malignant astrocytoma cell invasion of normal brain, astrocytic expression of u-PAR and u-PA mRNAs were analyzed by riboprobe in situ hybridization in astrocytoma and non-neoplastic brain biopsies. In eight of eight malignant astrocytomas (glioblastomas), u-PAR and u-PA mRNA expression was demonstrated, whereas in seven non-neoplastic brain biopsies, u-PAR and u-PA mRNAs were not expressed. In one of four low grade and all anaplastic astrocytomas u-PAR mRNA was expressed, although u-PA mRNA was undetectable. Consistent with the mRNA detection, u-PAR and u-PA proteins were expressed by malignant astrocytes in five of five glioblastoma biopsies. To study the tumor margin, U-251MG glioblastoma cells were propagated intracerebrally in a severe combined immunodeficient mouse xenograft (28 days), and u-PA mRNA was found to localize predominantly to the leading tumor edge, whereas u-PAR mRNA was expressed throughout the tumor. Furthermore, adherent human U-251MG glioblastoma cells in vitro expressed u-PAR and u-PA proteins, which localized to sites of integrin alpha nu beta 3 cell-matrix contacts. These data indicate that co-expression of u-PAR and u-PA mRNAs and proteins marks the malignant astrocyte phenotype and that u-PA bound to u-PAR may play a role in glioblastoma cell invasion of normal brain by virtue of its expression at the leading tumor edge.     

Expression of KIT Receptor Tyrosine Kinase in Endothelial Cells of Juvenile Brain Tumors

KIT receptor tyrosine kinase is expressed in tumor endothelial cells of adult glioblastomas, but its expression in pediatric brain tumor endothelial cells is unknown. We assessed expression of KIT, phosphorylated KIT, stem cell factor (SCF) and vascular endothelial growth factor receptor-2 (VEGFR-2) in 35 juvenile pilocytic astrocytomas and 49 other pediatric brain tumors using immunohistochemistry, and KIT messenger RNA (mRNA) using in situ hybridization. KIT and phospho-KIT were moderately or strongly expressed in tumor endothelia of 37% and 35% of pilocytic astrocytomas, respectively, whereas marked SCF and VEGFR-2 expression was uncommon. KIT mRNA was detected in tumor endothelial cells. Tumor endothelial cell KIT expression was strongly (P < 0.01) associated with endothelial cell phospho-KIT and SCF expression, and with tumor KIT (P = 0.0011) and VEGFR-2 expression (P = 0.022). KIT and phospho-KIT were present in endothelia of other pediatric brain tumors, notably ependymomas. Endothelial cell KIT expression was associated with a young age at diagnosis of pilocytic astrocytoma or ependymoma, and it was occasionally present in histologically normal tissue of the fetus and children. We conclude that KIT is commonly present in endothelial cells of juvenile brain tumors and thus may play a role in angiogenesis in these neoplasms.     

Supratentorial Pilocytic Astrocytomas, Astrocytomas, Anaplastic Astrocytomas and Glioblastomas are Characterized by a Differential Expression of S100 Proteins

The levels of expression of the S100A1, S100A2, S100A3, S100A4, S100A5, S100A6 and S100B proteins were immunohistochemically assayed and quantitatively determined in a series of 95 astrocytic tumors including 26 World Health Organization (WHO) grade I (pilocytic astrocytomas), 23 WHO grade II (astrocytomas), 25 WHO grade III (anaplastic astrocytomas) and 21 WHO grade IV (glioblastomas) cases. The level of the immunohistochemical expression of the S100 proteins was quantitatively determined in the solid tumor tissue (tumor mass). In addition twenty blood vessel walls and their corresponding perivascular tumor astrocytes were also immunohistochemically assayed for 10 cases chosen at random from each of the four histopathological groups. The data showed modifications in the level of S100A3 protein expression; these modifications clearly identified the pilocytic astrocytomas from WHO grade II-IV astrocytic tumors as a distinct biological group. Modifications in the level of S100A6 protein expression enabled a clear distinction to be made between low (WHO grade I and II) and high (WHO grade III and IV) grade astrocytic tumors. Very significant modifications occurred in the level of S100A1 protein expression (and, to a lesser extent, in their of the S100A4 and S100B proteins) in relation to the increasing levels of malignancy. While the S100A5 protein was significantly expressed in all the astrocytic tumors (but without any significant modifications in the levels of malignancy), the S100A2 protein was never expressed in these tumors. These data thus indicate that several S100 proteins play major biological roles in human astrocytic tumors.