WHO Grade III (who + grade_iii)

Distribution by Scientific Domains

Selected Abstracts

J1-31 protein expression in astrocytes and astrocytomas

Shanop Shuangshoti
J1-31 is one of the astrocytic proteins, the expression of which has not been evaluated in astrocytomas. In the present study, we studied the expression of J1-31 protein in astrocytes and astrocytomas in comparison with GFAP, p53 and Ki-67. Materials consisted of formalin-fixed paraffin-embedded tissue specimens that included five cases of normal brain, 17 of gliosis, 15 of pilocytic astrocytoma (WHO grade I), 26 of low-grade diffuse astrocytoma (WHO grade II), four of anaplastic astrocytoma (WHO grade III), and eight of glioblastoma (WHO grade IV). GFAP was highly expressed in all specimens examined. The anti-J1-31 antibody exhibited strong cytoplasmic staining of reactive gliosis in 17/17 (100%) cases with a higher intensity of staining than that observed in the adjacent normal astrocytes. The antibody showed reactivity with tumor cells in 12/15 (80%) cases of pilocytic astrocytoma, although intensity of staining was generally weaker and more focal than observed in reactive gliosis. J1-31-positive tumor cells were detected in only 9/26 (35%) cases of the low-grade diffuse astrocytoma and none of the cases of anaplastic astrocytoma and glioblastoma. Increasing Ki-67 indices paralleled advancing tumor grades. p53 protein was expressed more commonly in infiltrating astrocytomas compared to pilocytic astrocytoma. In conclusion, down-regulation of J1-31 expression correlates with advancing grade of astrocytomas. The result suggests this protein plays some role in astrocytes that is progressively lost in malignant progression. The anti-J1-31 antibody may help further our understanding of astrocytes in disease and may be useful as an aid in the pathologic diagnosis of astrocytic lesions. [source]

Identification and Functional Characterization of microRNAs Involved in the Malignant Progression of Gliomas

Bastian Malzkorn
Abstract Diffuse astrocytoma of World Health Organization (WHO) grade II has an inherent tendency to spontaneously progress to anaplastic astrocytoma WHO grade III or secondary glioblastoma WHO grade IV. We explored the role of microRNAs (miRNAs) in glioma progression by investigating the expression profiles of 157 miRNAs in four patients with primary WHO grade II gliomas that spontaneously progressed to WHO grade IV secondary glioblastomas. Thereby, we identified 12 miRNAs (miR-9, miR-15a, miR-16, miR-17, miR-19a, miR-20a, miR-21, miR-25, miR-28, miR-130b, miR-140 and miR-210) showing increased expression, and two miRNAs (miR-184 and miR-328) showing reduced expression upon progression. Validation experiments on independent series of primary low-grade and secondary high-grade astrocytomas confirmed miR-17 and miR-184 as promising candidates, which were selected for functional analyses. These studies revealed miRNA-specific influences on the viability, proliferation, apoptosis and invasive growth properties of A172 and T98G glioma cells in vitro. Using mRNA and protein expression profiling, we identified distinct sets of transcripts and proteins that were differentially expressed after inhibition of miR-17 or overexpression of miR-184 in glioma cells. Taken together, our results support an important role of altered miRNA expression in gliomas, and suggest miR-17 and miR-184 as interesting candidates contributing to glioma progression. [source]

Hypermethylation and Transcriptional Downregulation of the TIMP3 Gene is Associated with Allelic Loss on 22q12.3 and Malignancy in Meningiomas

Dimitri Barski
Abstract The gene for the tissue inhibitor of metalloproteinase 3 (TIMP3) on 22q12.3 had been reported to be inactivated by promoter methylation in various types of cancers, with controversial findings in meningiomas. We performed direct sodium bisulfite sequencing in a series of 50 meningiomas, including 27 benign meningiomas [World Health Organization (WHO) grade I], 11 atypical meningiomas (WHO grade II) and 12 anaplastic meningiomas (WHO grade III), and found hypermethylation of TIMP3 in 67% of anaplastic meningiomas, but only 22% of atypical and 17% of benign meningiomas. Moreover, TIMP3 methylation scores were significantly inversely correlated with TIMP3 mRNA expression levels (P = 0.0123), and treatment of the meningioma cell line Ben-Men-1 with demethylating agents induced an increased TIMP3 mRNA expression. TIMP3 is located in the chromosomal band 22q12, the allelic loss of which occurs early in meningioma tumorigenesis and preferentially targets the NF2 tumor suppressor gene. In our tumor panel, all meningiomas with TIMP3 hypermethylation,except for a single case,exhibited allelic losses on 22q12.3. Thus, TIMP3 inactivation by methylation seems fairly exclusive to meningiomas with allelic losses on 22q12 but,in contrast to NF2 mutation,appears to be involved in meningioma progression as it is associated with a more aggressive, high-grade meningioma phenotype. [source]

Allelic Gain and Amplification on the Long Arm of Chromosome 17 in Anaplastic Meningiomas

Rainer Büschges
Using comparative genomic hybridization (CGH) we have previously identified amplification at 17q21-qter as a common aberration in anaplastic meningiomas but not in atypical or benign meningiomas (19). To define the amplified genomic region, we analyzed 44 meningeal tumors, including 7 benign meningiomas of World Health Organization (WHO) grade I, 19 atypical meningiomas (WHO grade II) and 18 anaplastic meningiomas (WHO grade III) at 46 chromosome 17 loci (including 42 17q loci). In line with the CGH data we found evidence of increased numbers of alleles on 17q. The incidence rose with malignancy grade, culminating at 61% (11 of 18 cases) in the anaplastic meningioma group. The majority of cases showing increased allele numbers had, on average, low-level allelic gains (relative increase in allele dosage of 2- to 5-fold). Amplification of alleles (defined here as an average relative increase in allele dosage of more than 5 times) was detected in 2 anaplastic meningiomas. The amplification patterns in these tumors defined a number of common regions of amplification/increased allele copy number, the best defined include one between D17S790 and D17S1607 and one between D17S1160 and PS6K. Real-time PCR analysis of the PS6K candidate gene revealed no high-level amplification despite this affecting adjacent loci. Our findings are fundamental for the identification of the gene(s) in 17q22-q23 that is (are) the target(s) for increased copy number in anaplastic meningiomas and possibly other tumor types. [source]

Low Frequency of Chromosomal Imbalances in Anaplastic Ependymomas as Detected by Comparative Genomic Hybridization

Stefanie Scheil
We screened 26 ependymomas in 22 patients (7 WHO grade I, myxopapillary, myE; 6 WHO grade II, E; 13 WHO grade III, anaplastic, aE) using comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). 25 out of 26 tumors showed chromosomal imbalances on CGH analysis. The chromosomal region most frequently affected by losses of genomic material clustered on 13q (9/26). 6/7 myE showed a loss on 13q14-q31. Other chromosomes affected by genomic losses were 6q (5/26), 4q (5/26), 10 (5/26), and 2q (4/26). The most consistent chromosomal abnormality in ependymomas so far reported, is monosomy 22 or structural abnormality 22q, identified in approximately one third of Giemsabanded cases with abnormal karyotypes. Using FISH, loss or monosomy 22q was detected in small subpopulations of tumor cells in 36% of cases. The most frequent gains involved chromosome arms 17 (8/26), 9q (7/26), 20q (7/26), and 22q (6/26). Gains on 1q were found exclusively in pediatric ependymomas (5/10). Using FISH, MYCN proto-oncogene DNA amplifications mapped to 2p23-p24 were found in 2 spinal ependymomas of adults. On average, myE demonstrated 9.14, E 5.33, and aE 1.77 gains and/or losses on different chromosomes per tumor using CGH. Thus, and quite paradoxically, in ependymomas, a high frequency of imbalanced chromosomal regions as revealed by CGH does not indicate a high WHO grade of the tumor but is more frequent in grade I tumors. [source]