Expression of urokinase-type plasminogen activator receptor (uPAR) in primary central nervous system neoplasms.

The cellular receptor for urokinase-type plasminogen activator receptor (uPAR) is a member of the glycosylphosphatidylinositol (GPI) anchored protein family. It is a specific cell surface receptor for its ligand, urokinase-type plasminogen activator, which catalyzes the formation of plasmin from plasminogen to generate the proteolytic cascade and leads to the breakdown of the extracellular matrix. uPAR has been shown to correlate with a propensity to tumor invasion and metastasis in several types of non-central nervous system tumors. In this study, the authors examined the immunohistochemical expression of uPAR in 65 primary brain tumors (5 pilocytic astrocytomas, 5 diffuse astrocytomas, 6 anaplastic astrocytomas, 8 glioblastomas, 5 oligodendrogliomas, 4 oligoastrocytomas, 6 anaplastic oligoastrocytomas, 4 gangliogliomas, 4 ependymomas, 5 medulloblastomas, 6 schwannomas, 5 meningiomas, 2 atypical meningiomas). The specimens were evaluated for intensity of immunostaining (0-3 scale), cellular localization of staining, and specific or unique patterns of staining. Some degree of uPAR expression was observed in all tumors. A significant positive correlation (P = 0.0006) between tumor grade and staining intensity was identified within the astrocytoma/glioblastoma subgroup, suggesting a possible correlation with anaplastic change and propensity to tumor invasion. Expression of uPAR in nonmalignant, noninvasive tumors such as schwannoma and meningioma suggests that uPAR may have other biologic functions in addition to promotion of tumor invasion.     

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.     

Cytogenetic and loss of heterozygosity studies in ependymomas, pilocytic astrocytomas, and oligodendrogliomas.

Cytogenetic and/or loss of heterozygosity studies were performed on 13 ependymomas, 11 pilocytic astrocytomas, and 18 oligodendrogliomas. Loss of chromosome 22 was the most frequent genetic abnormality among the ependymomas. We found no consistent genetic abnormality in pilocytic astrocytomas. The most common genetic abnormality in oligodendrogliomas was loss of a portion of chromosome 19. Each informative oligodendroglioma had loss of alleles mapped to the long arm (q) of chromosome 19. One oligodendroglioma had an apparent homozygous deletion of the D19S8 locus. Our results, when combined with those in the literature, indicate that chromosomes 9, 11, and 22 may harbor genes important for the pathogenesis of ependymomas and that 19q probably harbors a gene important for the pathogenesis of oligodendrogliomas.     

Nogo-A: a useful marker for the diagnosis of oligodendroglioma and for identifying 1p19q codeletion

The differential diagnosis between oligodendrogliomas and other gliomas remains a critical issue. The aim of this study is to verify the diagnostic value of Olig-2, Nogo-A, and synaptophysin and their role in identifying 1p19q codeletion. A total of 168 cases of brain tumors were studied: 24 oligodendrogliomas, 23 anaplastic oligodendrogliomas, 2 oligoastrocytomas, 2 anaplastic oligoastrocytomas, 30 glioblastoma multiforme, 2 diffuse astrocytomas, 4 anaplastic astrocytomas, 10 pilocytic astrocytomas, 9 ependymomas, 12 anaplastic ependymomas, 10 central neurocytomas, 10 meningiomas, 10 choroid plexus papillomas, 10 dysembryoplastic neuroepithelial tumors, and 10 metastases. All cases were immunostained with Olig-2, Nogo-A, and synaptophysin. In 79 cases, the status of 1p/19q had already been assessed by fluorescence in situ hybridization. Thus, in selected cases, fluorescence in situ hybridization was repeated in areas with numerous Nogo-A-positive neoplastic cells. Nogo-A was positive in 18 (75%) of 24 oligodendrogliomas, 8 (80%) of 10 dysembryoplastic neuroepithelial tumors, 6 (20%) of 30 glioblastoma multiforme, and 2 (20%) of 10 pilocytic astrocytomas. Olig-2 stained 22 (91.6%) of 24 oligodendrogliomas and all dysembryoplastic neuroepithelial tumors but also 24 (80%) of 30 glioblastoma multiforme and 8 (80%) of 10 pilocytic astrocytomas. Finally, synaptophysin stained 13 (54.1%) of 24 oligodendrogliomas, 3 (10%) of 30 glioblastoma multiforme, 1 (10%) of 10 pilocytic astrocytomas, and all neurocytomas. Among the 79 tested cases, original fluorescence in situ hybridization showed 1p/19q codeletion in 12 (52.2%) of 23 oligodendrogliomas, 8 (38%) of 21 anaplastic oligodendrogliomas, and 1 (4%) of 25 glioblastoma multiforme. However, after carrying out the Nogo-A-driven fluorescence in situ hybridization, 1p/19q codeletion was observed in 8 additional cases. Nogo-A is more useful and specific than Olig-2 in differentiating oligodendrogliomas from other gliomas. Furthermore, using a Nogo-A-driven fluorescence in situ hybridization analysis, it is possible to identify a larger number of 1p19q codeletions in gliomas.     

Molecular Markers of Gliomas

Gliomas are invasive recurrent brain tumors with high lethality. Gliomas have been morphologically divided into astrocytomas, oligodendrogliomas, and mixed oligoastrocytomas. Gliomas are graded according to the criteria of the World Health Organization criteria as grade I (pilocytic astrocytomas), grade II (low-grade gliomas), grade III (high-grade gliomas), and grade IV (glioblastoma). The mutations of IDH1/2 and TP53 genes and MGMT methylation have been described as prognostic markers of glioma. The aim of the present review is to analyze research and experimental results (Scopus, Web of Science, Pubmed) concerning somatic mutations, aberrant regulation of gene expression of signal pathways, diagnostic and prognostic markers of glioma progression and characterizing various morphological types and grades of glioma. In particular, the specificities of medulloblastomas and ependymomas have been considered in the present review.     

100例中枢神经系统肿瘤的胶质纤维酸性蛋白免疫组化观察

对100例中枢神经系统肿瘤进行GFAP免疫组化观察。结果表明,GFAP主要分布于各种类型的星形细胞瘤,多形性胶质母细胞瘤,混合性胶质瘤及部分室管膜瘤。GFAP染色强度与瘤细胞分化程度有关。本文还探讨了室管膜瘤与少突胶质瘤存在GFAP问题。研究表明GFAP可作为诊断神经胶质瘤的一种有用标记物。     

Integrin alpha(v)beta(3) expression in colon carcinoma correlates with survival.

Integrin alpha(v)beta(3) is expressed by newly formed blood vessels in diseased and neoplastic tissue and can therefore be used as a marker for angiogenesis. We investigated its expression on the vasculature of 40 colon carcinomas using the anti-alpha(v)beta(3)-specific monoclonal antibody LM609. The average relapse-free interval and overall survival in patients suffering from colon carcinomas with high vascular expression of alpha(v)beta(3) integrin was significantly reduced compared with that in patients with low alpha(v)beta(3) integrin expressing tumor vasculature. Moreover, the expression level of alpha(v)beta(3) integrin correlated with the presence of liver metastases. In conclusion, we propose vascular expression of alpha(v)beta(3) integrin as a prognostic indicator for colon carcinoma.     

Significance of immunohistochemistry for neuro-oncology. VI. Occurrence, localization and distribution of glial fibrillary acid protein (GFAP) in 820 tumors

In a retrospective study 820 tumors were immunohistochemically examined with anti-GFAP. All 224 astrocytomas and 105 of 112 glioblastomas were, at least focally, positive. 72% of ependymomas and 64% of oligodendrogliomas contained tumor cells which expressed GFAP. In such entities the reaction is dependent on the histologic subtype. Only 26 of 114 medulloblastomas (22.8%) demonstrated scattered GFAP positive cells. GFAP was also demonstrated in the CNS in gangliogliomas, monstrocellular sarcomas, 3 of 6 PNET, one non-classifiable tumor in a child, 1 plexus papilloma, in scattered stromal cells in 15 of 26 hemangioblastomas as well as in the mature glial component of intracranial germ cell tumors. Outside of the CNS there was evidence of GFAP in 3 cases with nasal glial heterotopy and in the myxoidal part of a pleomorphic salivary gland adenoma. Neoplasms which proved negative to GFAP in our series included purely neural differentiated tumors meningioma, neurolemmomas, chordomas, paragangliomas, sarcomas, lymphomas, melanomas and carcinoma metastases. Separating GFAP-positive reactive astrocytes from the actual tumor cells has proved to be a problem in the routine use of GFAP in differential diagnosis. Absence of an immunohistochemical response does not exclude a tumor of glial origin. Tissue samples which are too small, particularly in the case of anaplastic astrocytomas and glioblastomas can give false negative results.     

Galectin-3 as an immunohistochemical tool to distinguish pilocytic astrocytomas from diffuse astrocytomas, and glioblastomas from anaplastic oligodendrogliomas

The distinction of astrocytomas and oligodendrogliomas, mainly pilocytic astrocytomas (PILOs) from infiltrating astrocytomas and oligodendrogliomas (ODs), and high-grade oligodendrogliomas from glioblastomas (GBMs), poses a serious clinical problem. There is no useful immunohistochemical (IHC) marker to differentiate these gliomas, and sometimes the differential diagnosis between them is arbitrary. We identified galectin-3 (Gal-3) as a possible tool to differentiate them based on gene expression profiles of GBMs. We confirmed the differential expression in 45 surgical samples (thirteen GBMs; seven PILOs; 5 grade II ODs; 5 anaplastic oligodendrogliomas [AODs], including 2 Oligo-astrocytomas; 8 diffuse astrocytomas [ASTs], and 7 non-neoplastic samples) by quantification of Gal-3 gene expression by real-time quantitative PCR (rt-PCR). Higher expression of Gal-3 was observed in GBMs and PILOs than in OD, AODs and ASTs. The IHC expression of Gal-3 was evaluated in 90 specimens (fifteen PlLOs, fourteen ASTs, 10 anaplastic astrocytomas, fifteen GBMs, eleven ODs, fifteen AODs, and 10 dysembryoplastic neuroepithelial tumors). The mean labeling score for Gal-3 determined according to the percentage of labeled cells in the tumor bulk was significantly different in GBMs versus AODs and in PILOs versus ASTs. Hence, Gal-3 is differentially expressed in central nervous system tumors, making IHC detection of Gal-3 a useful tool in distinguishing between these gliomas.     

Secretagogin expression in tumours of the human brain and its coverings

Secretagogin is a recently described calcium-binding protein, which is expressed in some neurons of the human brain. In this study we systematically investigated secretagogin expression in 245 tumours of the human brain and its coverings using immunohistochemistry. We found focal or widespread secretagogin expression in tumour cells in 1/18 oligoastrocytomas, 1/19 oligodendrogliomas, 2/20 anaplastic oligodendrogliomas, 2/9 ependymomas, 2/11 anaplastic ependymomas, 2/10 glioblastomas, 3/11 gangliogliomas and 1/2 anaplastic gangliogliomas, 10/10 central neurocytomas, 5/10 classic medulloblastomas, 4/5 desmoplastic medulloblastomas, 3/5 large cell/anaplastic medulloblastomas, 3/5 neuroblastomas, 3/10 meningiomas, 2/10 haemangioblastomas, and 13/19 pituitary adenomas. Further, we observed secretagogin expression in endothelial cells in 5/10 meningiomas, 2/5 haemangiopericytomas, and 2/10 haemangioblastomas. We detected no secretagogin expression in fibrillary astrocytoma, pilocytic astrocytoma, DNT, pineocytoma, pineoblastoma, subependymal giant cell astrocytoma (SEGA), atypical teratoid/rhabdoid tumour (AT/RT), or primary central nervous system lymphoma (PCNSL). We conclude that secretagogin is differentially expressed in human neuronal, glial, and embryonal brain tumours, meningial neoplasms and pituitary adenomas. Our findings indicate that secretagogin is involved in the calcium metabolism of tumour cells and endothelial cells in a subset of neoplasms of the brain and its coverings. Anti-secretagogin immunohistochemistry does not seem to be helpful in most differential diagnostic situations in surgical neuropathology.     

Lipocortin-1 immunoreactivity in central and peripheral nervous system glial tumors

We examined the cellular distribution of lipocortin-1 (L-1), a major physiologic substrate for the epidermal growth factor receptor/kinase, in 122 central nervous system (CNS) and peripheral nervous system (PNS) neoplasms using the peroxidase-antiperoxidase technique with a polyclonal antibody specific for L-1. Extensive L-1 immunoreactivity was demonstrated in many CNS tumors; in 11 of 21 glioblastoma multiformes, in five of 12 anaplastic astrocytomas, and in five of 14 astrocytomas. Significant numbers of immunoreactive ependymocytes or astrocytes were also seen in six of 13 ependymomas. In contrast, no immunostaining was detected in the oligodendrocytes in any of ten oligodendrogliomas. PNS tumors, found in two of five malignant nerve sheath tumors, 13 of 15 schwannomas, 13 of 17 neurofibromas, and 14 of 15 traumatic neuromas, also contained considerable L-1 immunoreactivity in Schwann cells or mast cells. These findings raise the possibility that L-1 may participate in the proliferation or subsequent differentiation of neoplastic astrocytes, ependymocytes, and Schwann cells.     

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.     

Endometrial vascular and glandular expression of integrin alpha(v)beta3 in women with and without endometriosis

The integrin alpha(v)beta3 functions in both cell-cell and cell- extracellular matrix adhesion, and has reported roles in platelet aggregation, immune function, tissue repair, tumour invasion, angiogenesis and uterine receptivity. The aim of this study was to use immunohistochemistry to describe the vascular and glandular expression of integrin alpha(v)beta3 in formalin fixed, paraffin embedded endometrium obtained from women with (n = 29) and without (n = 24) endometriosis. The results showed a significant increase in the percentage of vessels expressing alpha(v)beta3 in the endometrium of women with endometriosis compared with controls (P = 0.0001). This difference was more pronounced in the secretory phase (P = 0.001) than the proliferative phase (P = 0.016). There was no correlation between vascular alpha(v)beta3 expression and the endothelial cell proliferation index (P > 0.05). Vascular sprouts were not observed in any of the 53 endometrial tissues obtained from women with or without endometriosis throughout the menstrual cycle. Results from semi- quantitative scoring of gland immunostaining showed that neither controls (P = 0.3329) nor the endometriosis group (P = 0.2260) had any significant changes in terms of alpha(v)beta3 expression between the different stages of the menstrual cycle. There was also no difference in glandular alpha(v)beta3 expression between women with and without endometriosis (P = 0.4302). These results provide evidence for increased endometrial angiogenesis in women with endometriosis compared with controls, and suggest that glandular expression of alpha(v)beta3 is not related to uterine receptivity per se.      

Nestin expression in neuroepithelial tumors

Nestin is a marker of early stages of neurocytogenesis. It has been studied in 50 neuroepithelial tumors, mostly gliomas of different malignancy grades, by immunohistochemistry, immunofluorescence, immunoblotting, and confocal microscopy and compared with GFAP and Vimentin. As an early marker of differentiation, Nestin is almost not expressed in diffuse astrocytomas, variably expressed in anaplastic astrocytomas and strongly and irregularly expressed in glioblastomas. Negative in oligodendrogliomas, it stains ependymomas and shows a gradient of expression in pilocytic astrocytomas. In glioblastomas, Nestin distribution does not completely correspond to that of GFAP and Vimentin with which its expression varies in tumor cells in a complementary way, as confirmed by confocal microscopy. Tumor cells can thus either derive from or differentiate toward the neurocytogenetic stages. Hypothetically, they could be put in relation with radial glia where during embriogenesis the three antigens are successively expressed. Completely negative cells of invasive or recurrent glioblastomas may represent malignant selected clones after accumulation of mutations or early stem cells not expressing antigens.     

Comparative analysis of NeuN immunoreactivity in primary brain tumours: conclusions for rational use in diagnostic histopathology

AIMS: NeuN is considered to be a marker of neuronal differentiation in brain tumours. Our aim was to perform, for the first time, a systematic and comparative analysis of NeuN expression in all major brain tumour subtypes to provide guidance for the rational use of NeuN immunohistochemistry in diagnostic histopathology. METHODS AND RESULTS: Anti-NeuN immunohistochemistry was performed on paraffin-embedded biopsy specimens of 106 diffuse astrocytomas, 100 pilocytic astrocytomas, 107 ependymomas, 59 1p-aberrant oligodendroglial neoplasms, 115 glioblastomas, 115 medulloblastomas, 14 gangliogliomas/gangliocytomas and 10 central neurocytomas. We found no NeuN expression in pilocytic astrocytoma, whereas all other investigated tumour subtypes showed focal or widespread expression in varying proportions of cases. Comparing NeuN expression in clear cell tumours, widespread NeuN expression had a positive predictive value of 76.9% (95% confidence interval 46.2, 95.0) for central neurocytoma. Lack of NeuN expression had a positive predictive value of 87.3% (76.5, 94.4) for oligodendroglioma. CONCLUSIONS: Immunohistochemistry can detect NeuN expression in all major brain tumour subtypes except pilocytic astrocytoma. In the individual case, assessment of NeuN expression may be helpful in the differential diagnosis of clear cell primary brain tumours but does not seem to be useful for the differential diagnosis of other brain tumour subtypes.     

Chromosome abnormalities in low-grade central nervous system tumors.

Ependymomas, oligodendrogliomas, and low-grade astrocytomas are slow-growing central nervous system (CNS) tumors that occur in both adults and children, whereas craniopharyngiomas and choroid plexus papillomas occur predominantly in children. We examined karyotypes of 32 of these low-grade tumors, including ten oligodendrogliomas, six ependymomas, 11 low-grade astrocytomas, four craniopharyngiomas, and one choroid plexus papilloma. Only normal karyotypes were obtained from 6 oligodendrogliomas. The rest had normal stemlines; three tumors had 45,X,-Y sidelines and one tumor had a sideline of monosomy 22. The most frequent abnormalities in the ependymomas were +7 (three tumors), -21 (two tumors), -22 (two tumors), and del(9)(p22) (two tumors). Gains of chromosome 7 and deletions of 9p were found more often in high-grade gliomas. Seven low-grade astrocytomas had normal stemlines, two had chromosome 7 abnormalities, a pilocystic astrocytoma had +der(15), and one tumor had a -Y sideline. The four craniopharyngiomas and one choroid plexus tumor were all apparently normal. The cytogenetics of low-grade CNS tumors differ from higher grade gliomas in that most low-grade tumors show little deviation from the normal karyotype.     

Karyotypes in 90 human gliomas.

Cytogenetic studies were performed on 90 human gliomas including 26 astrocytomas, 12 oligodendrogliomas, three oligo-astrocytomas, seven ependymomas, eight pilocytic astrocytomas, and 33 malignant gliomas (anaplastic astrocytomas and glioblastomas). The most common abnormalities were trisomy 7 in 23 cases, monosomy 22 in 15 cases, losses of the Y chromosome in 19 of 50 male cases, and losses of the X chromosome in 10 of 39 female cases. There are evident differences between the particular subgroups of gliomas. Monosomy 10 and double minutes are typical for malignant gliomas. The 58 determined chromosomal breakpoints were located on 45 different sites. Chromosomes 1, 9, 6, 3, 10, and 17 were predominantly involved.     

Epigenetic changes in pilocytic astrocytomas and medulloblastomas

Aberrant methylation of CpG islands located in promoter regions represents one of the major mechanisms for silencing of cancer-related genes in tumour cells. We determined the frequency of aberrant CpG island methylation of several tumour-associated genes: MGMT, GSTP1, DAPK, p14ARF, THBS1, TIMP-3, p73, p16INK4A, RB1 and TP53 in 24 neurogenic tumours consisting of pilocytic astrocytomas (n=13) and medulloblastomas (n=11). The methylation index (number methylated genes/total genes analysed) displayed slight differences (0.18 and 0.25, respectively), and the profile of methylated genes in the two neoplasms was distinct, as predicted. The main differences involved the methylation rate of GSTP1 (0% in pilocytic astrocytomas vs. 18% medulloblastomas) and p14ARF (0% in pilocytic astrocytomas vs. 45% in medulloblastomas) genes. Pilocytic astrocytomas also demonstrated some differences when compared to methylation data from other astrocytic tumours, primarily regarding the MGMT methylation rate. Despite the fact that these differences do not show specific tumour-associated gene methylation patterns, our findings should help us understand the pathogenic mechanisms of both neurogenic neoplasm types.