Correlation between progression free survival and dynamic susceptibility contrast MRI perfusion in WHO grade III glioma subtypes

The purpose of this study was to determine whether dynamic susceptibility contrast MR perfusion relative cerebral blood volume (rCBV) correlates with prognosis of World Health Organization (WHO) grade III glial tumors and their different subtypes. Retrospective evaluation of pre-treatment tumor rCBV derived from dynamic susceptibility contrast MR perfusion was performed in 34 patients with histopathologically diagnosed WHO grade III glial tumors (anaplastic astrocytomas (n = 20), oligodendrogliomas (n = 4), and oligoastrocytomas (n = 10)). Progression free survival was correlated with rCBV using Spearman rank analysis. ROC curve analysis was performed to determine the operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time. For all grade III tumors (n = 34) the mean rCBV was 2.51 with a progression free survival of 705.5 days. The mean rCBV of anaplastic astrocytomas was 2.47 with progression free survival 495.2 days. In contrast, the mean rCBV for oligodendroglial tumors was 2.56 with a progression free survival of 1005.6 days. Although there was no significant correlation between rCBV and progression free survival among all types of grade III gliomas (P = 0.12), among anaplastic astrocytomas there was a significant correlation between pretreatment rCBV and progression free survival with correlation coefficient of ?0.51 (P = 0.02). The operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time (446.5 days) was 2.86 with 78 % accuracy and there was a significant difference between the survival of patients with anaplastic astrocytomas in the dichotomized groups (P = 0.0009). Pre-treatment rCBV may serve as a prognostic imaging biomarker for anaplastic astrocytomas, but not grade III oligodendroglioma tumors.     

High expression of the stem cell marker nestin is an adverse prognostic factor in WHO grade II–III astrocytomas and oligoastrocytomas

Infiltrating astrocytomas and oligoastrocytomas of low to anaplastic grade (WHO grades II and III), in spite of being associated with a wide range of clinical outcomes, can be difficult to subclassify and grade by the current histopathologic criteria. Unlike oligodendrogliomas and anaplastic oligodendrogliomas that can be identified by the 1p/19q codeletion and the more malignant glioblastomas (WHO grade IV astrocytomas) that can be diagnosed solely based on objective features on routine hematoxylin and eosin sections, no such objective criteria exist for the subclassification of grade II–III astrocytomas and oligoastrocytomas (A+OA II–III). In this study, we evaluated the prognostic and predictive value of the stem cell marker nestin in adult A+OA II–III (n = 50) using immunohistochemistry and computer-assisted analysis on tissue microarrays. In addition, the correlation between nestin mRNA level and total survival was analyzed in the NCI Rembrandt database. The results showed that high nestin expression is a strong adverse prognostic factor for total survival (p = 0.0004). The strength of the correlation was comparable to but independent of the isocitrate dehydrogenase 1/2 (IDH 1/2) mutation status. Histopathological grading and subclassification did not correlate significantly with outcome, although the interpretation of this finding is limited by the fact that grade III tumors were treated more aggressively than grade II tumors. These results suggest that nestin level and IDH 1/2 mutation status are strong prognostic features in A+OA II–III and possibly more helpful for treatment planning than routine histopathological variables such as oligodendroglial component (astrocytoma vs. oligoastrocytoma) and WHO grade (grade II vs. III).     

Histological classification of human gliomas: state of art and controversies

The histological classification of human gliomas remains in 2005 a challenge. The aim is to define the histological type of glioma (astrocytic, oligodendrocytic or mixed) and the grade in order to classify the patients and give them an accurate treatment. Although the standard remains the WHO classification, this classification suffered from lack of reproducibility among pathologists. In particular this classification does not take into account the intrinsic morphological heterogeneity of infiltrative gliomas and does not discriminate the tumour cells from the residual brain parenchyma. According to the WHO classification, infiltrative gliomas encompass astrocytic gliomas (diffuse astrocytomas grade II, anaplastic astrocytomas grade III and glioblastomas grade IV), oligodendroglial tumours (oligodendrogliomas grade II, anaplastic oligodendrogliomas grade III) and mixed gliomas (oligoastrocytomas grade II and anaplastic oligoastrocytomas grade III). Circumscribed gliomas mainly corresponds to pilocytic astrocytomas (grade I). In contrast, the Sainte Anne classification takes into account the macroscopic informations provided by imaging techniques and the tumour growth patterns. Three distinct tumour growth patterns may be seen in gliomas, type I: tumor tissue only, type II: tumour tissue and isolated tumor cells permeating the brain parenchyma (ITC) and type III: ITCs only and no tumor tissue. According to the Sainte Anne classification, gliomas are divided into astrocytic gliomas (pilocytic astrocytomas, structure type I, glioblastomas structure type II) and oligodendrogliomas and mixed oligoastrocytomas (grade A: lack of contrast enhancement and lack of endothelial hyperplasia, structure type III; and grade B: contrast enhancement or endothelial hyperplasia, structure type II and III). In the future the glioma classification has to be unique and should take into account clinical data, neuroradiological and histological features and results of molecular biology.     

Molecular pathogenesis of pediatric astrocytic tumors

Astrocytomas are the most common pediatric brain tumors, accounting for 7%-8% of all childhood cancers. Relatively few studies have been performed on their molecular properties; therefore, classification of pediatric astrocytic tumors into genetic subtypes similar to that of adult tumors remains to be defined. Here, we report an extensive characterization of 44 pediatric astrocytomas--16 diffuse astrocytomas (WHO grade II), 10 anaplastic astrocytomas (WHO grade III), and 18 glioblastomas (WHO grade IV)--in terms of genetic alterations frequently observed in adult astrocytomas. Some form of p53 mutation was found in three diffuse astrocytomas, in three anaplastic astrocytomas, and in six glioblastomas examined; PTEN mutations were detected only in two glioblastomas. EGFR amplification was detected in only one anaplastic astrocytoma and two glioblastomas, but no amplification was observed for the PDGFR-alpha gene. Loss of heterozygosity (LOH) on 1p/19q and 10p/10q was less common in pediatric astrocytic tumors than in those seen in adults, but the frequency of LOH on 22q was comparable, occurring in 44% of diffuse astrocytomas, 40% of anaplastic astrocytomas, and 61% of glioblastomas. Interestingly, a higher frequency of p53 mutations and LOH on 19q and 22q in tumors from children six or more years of age at diagnosis was found, compared with those from younger children. Our results suggest some differences in children compared to adults in the genetic pathways leading to the formation of de novo astrocytic tumors. In addition, this study suggests potentially distinct developmental pathways in younger versus older children.     

Prognostic variables in oligodendroglial tumors: a single-institution study of 95 cases

We analyzed the relationships among clinical variables, histology, 1p/19q status, and outcome in 95 patients with oligodendroglial tumors. The study enrolled adult patients who underwent first-time surgery for a supratentorial oligodendroglial tumor at Oslo University Hospital, Rikshospitalet. Tumors were: 27 oligodendrogliomas, WHO grade II; 32 oligoastrocytomas, WHO grade II; 16 anaplastic oligodendrogliomas, WHO grade III; 14 anaplastic oligoastrocytomas, WHO grade III; and 6 glioblastomas with a major oligodendroglial component, WHO grade IV. The clinical files were reviewed. Three neuropathologists evaluated the histological slides independently. Loss-of-heterozygosity analysis for 1p and 19q was performed by PCR. Favorable prognostic factors from univariate analyses included seizures as presenting symptom, female sex, location in the frontal lobe, low WHO grade, classic histology, absence of gemistocytic cells, and combined 1p/19q loss. Solitary 19q loss was a negative prognostic marker. 1p/19q status was of prognostic significance in both tumors with classic and nonclassic oligodendroglial histology. In the multivariate analysis, WHO grade II (P< .001), frontal tumor location (P= .002), and combined 1p/19q loss (P< .001) remained favorable prognostic variables. Our results suggest that tumor location, WHO grade, and 1p/19q status are important independent variables associated with survival in oligodendroglial tumors. The study suggests that solitary 19q loss is a negative prognostic variable and that 1p/19q loss is associated with prolonged survival also in oligodendroglial tumors without classic histology.     

Deletion mapping of chromosome 19 in human gliomas

There is evidence that a putative glioma tumor suppressor locus resides on the long arm of chromosome 19. We present data on 161 gliomas from IS6 patients, which were studied by microsatellite analysis for loss of heterozygosity (LOH) on chromosome 19. Eight loci on the long arm and 2 loci on the short arm of chromosome IV were examined. LOH on I9qwas observed in 3/19 astrocytomas (WHO grade II), 12/27 anaplastic astrocytomas (WHO grade III), 16/76 cases of glioblastoma multiforme WHO (grade IV), 4/9 oligodendrogliomas (WHO grade II), 3/5 anaplastic oligodendrogliomas (WHO grade III), 5/9 mixed oligo-astrocytomas (WHO grade II) and 8/10 anaplastic oligo-astrocytomas (WHO grade III). While 31 of the tumors with LOH on chromosomal arm I9q exhibited allelic loss at every informative locus, 20 tumors showed terminal or interstitial deletions. In contrast to astrocytomas and glioblastomas, tumors with an oligodendroglial component had predominantly lost the entire long arm of chromosome 19. The common region of overlap in gliomas was located on 19q 13.2-q 13.4 between the markers D 19S 178 and D 19S 180. Our data confirm the involvement of a putative tumor suppressor gene on chromosomal arm 19q in gliomas and assign this gene to 19q 13.2-q 13.4.     

Correlation of chromosomal imbalances by comparative genomic hybridization and expression of EGFR, PTEN, p53, and MIB-1 in diffuse gliomas

The histological subclassification of gliomas is increasingly assisted by the underlying molecular genetics which has major importance in guiding clinical management of the disease. However, the assessment of several molecular events for improving clinical care remains a challenge. Herein, we report on comparative genomic hybridization (CGH) and immunohistochemical (IHC) assessment of EGFR, PTEN, p53, and MIB-1 expression in 13 oligodendrogliomas (10 WHO grade II, 3 WHO grade III), one oligoastrocytoma (WHO grade III) and 23 high-grade astrocytomas (3 WHO grade III, 20 glioblastoma multiforme). The most frequent imbalances in oligodendroglial tumors including the oligoastrocytic case were, in decreasing order of frequency, +7q, -1p, and -4q and in astrocytomas +7q, -10q, +7p, -9p, -10p, +20q, and +20p. Some individual imbalances were associated with increasing numbers of chromosomal changes, that were +7q in both oligodendrogliomas and astrocytomas, and -9p, -10q, +20p, and +20q in astrocytomas. The markers p53 and MIB-1 were significantly higher expressed in astrocytomas than in oligodendrogliomas and expression levels of p53 and EGFR were inversely associated within the astrocytic group. In addition, p53 overexpression correlated positively with +7q and negatively with -1p in the oligodendroglial group whereas EGFR overexpression correlated positively with -1p in the oligodendroglial and positively with +7p and -10p in the astrocytic group. Short overall survival was significantly associated with +7p and -10q in astrocytomas. Collectively, these results contribute to the increasing clinical relevance of assessing tumor biological markers in gliomas.     

Correlation of histology and molecular genetic analysis of 1p, 19q, 10q, TP53, EGFR, CDK4, and CDKN2A in 91 astrocytic and oligodendroglial tumors.

PURPOSE: The histological diagnosis of human gliomas is of great importance for estimating patient prognosis and guiding therapy but suffers from being subjective and, therefore, variable. We hypothesized that molecular genetic analysis could provide a more objective means to classify tumors and, thus, reduce diagnostic variability. EXPERIMENTAL DESIGN: We performed molecular genetic analysis on 91 nonselected gliomas for 1p, 19q, 10q, TP53, epidermal growth factor receptor, and cyclin-dependent kinase 4 abnormalities and compared with the consensus diagnoses established among four independent neuropathologists. RESULTS: There were six astrocytomas, seven anaplastic astrocytomas, 45 glioblastomas, 21 oligodendrogliomas, eight anaplastic oligodendrogliomas, three oligoastrocytomas, and one anaplastic oligoastrocytoma. Twenty-nine cases had either 1p or 19qloss of heterozygosity (LOH) while retaining both copies of 10q, of which 25 (86%) were histologically oligodendroglioma, anaplastic oligodendroglioma, oligoastrocytoma, or anaplastic oligoastrocytoma. As for the oligodendroglial tumors, unanimous agreement of the initial diagnoses was almost restricted to those cases with combined 1p/19qLOH, whereas all nine tumors without 1p loss initially received variable diagnoses. Interestingly, TP53 mutation was inversely related to 1pLOH in all gliomas (P = 0.0003) but not 19qLOH (P = 0.15). CONCLUSIONS: These data demonstrate that molecular genetic analysis of 1p/19q/10q/TP53 has significant diagnostic value, especially in detecting oligodendroglial tumors. In addition, 1pLOH and TP53 mutations in gliomas may be markers of oligodendroglial and astrocytic pathways, respectively, which may separate gliomas with the same histological diagnosis, especially oligodendroglial tumors and glioblastomas. Testing for those molecular genetic alterations would be essential to obtain more homogeneous sets of gliomas for the future clinical studies.     

Morphologic and molecular genetic aspects of oligodendroglial neoplasms

Morphologic criteria for diagnosing oligodendrogliomas and for classifying them as well-differentiated (World Health Organization grade II) and anaplastic (World Health Organization grade III) are well recognized. Nevertheless, applying these guidelines to specific cases often reveals discrepancies among different observers. In addition, whether a given tumor also contains an astrocytic component may be debatable. Loss of heterozygosity studies have demonstrated that oligodendroglial neoplasms have a high incidence of loss of the 1p and 19q chromosomal arms. Although loss of heterozygosity for portions of 19q are sometimes seen in astrocytic neoplasms, these tumors seldom show complete loss of 19q accompanied by loss of 1p. Loss of 9p or homozygous deletion of the CDKN2 gene or both are associated with anaplastic oligodendrogliomas, whereas loss of 17p or TP53 gene mutations or both are frequent in astrocytomas, but rare in oligodendrogliomas. These observations suggest that molecular genetic parameters could provide an objective, reproducible framework for classifying oligodendroglial neoplasms.     

Vascular Endothelial Growth Factor (VEGF) in Astrocytic Gliomas – A Prognostic Factor?

Survival in astrocytic gliomas is closely related to WHO tumor grade. Within one tumor grade, especially in grade II and III tumors, the clinical course is variable and can hardly be predicted by histological criteria. Neovascularization is a neuropathological hallmark in high grade gliomas and angiogenic factors may play an important role in malignant tumor progression. Therefore, 162 primary astrocytic gliomas (57 astrocytomas WHO grade II, 27 astrocytomas WHO grade III and 78 glioblastomas WHO grade IV) were investigated immunohistochemically for expression of vascular endothelial growth factor (VEGF), which is considered to represent the main angiogenic factor in astrocytic gliomas. Clinical data known to influence prognosis were documented. VEGF expression was found in 21 of 57 astrocytomas WHO grade II (36.8%), in 18 of 27 astrocytomas WHO grade III (66.7%) and in 50 of 78 glioblastomas (64.1%). A strong correlation between VEGF expression and survival was found within the whole study group, however, within one tumor grade no such correlation was obvious. In a multifactorial analysis VEGF expression was not found to be an independent prognostic factor in astrocytic gliomas.     

1p36 is a preferential target of chromosome 1 deletions in astrocytic tumours and homozygously deleted in a subset of glioblastomas

Astrocytic, oligodendroglial and mixed gliomas are the commonest gliomas in adults. They have distinct phenotypes and clinical courses, but as they exist as a continuous histological spectrum, differentiating them can be difficult. Co-deletions of total 1p and 19q are found in the majority of oligodendrogliomas and considered as a diagnostic marker and a prognostic indicator. The 1p status of astrocytomas has not yet been thoroughly examined. Using a chromosome 1 tile path array, we investigated 108 adult astrocytic tumours for copy number alterations. Total 1p deletions were rare (2%), however partial deletions involving 1p36 were frequently identified in anaplastic astrocytomas (22%) and glioblastomas (34%). Multivariate analysis showed that patients with total 1p deletions had significantly longer survival (P=0.005). In nine glioblastomas homozygous deletions at 1p36 were identified. No somatic mutations were found among the five genes located in the homozygously deleted region. However, the CpG island of TNFRSF9 was hypermethylated in 19% of astrocytic tumours and 87% of glioma cell lines. TNFRSF9 expression was upregulated after demethylation of glioma cell lines. Akt3 amplifications were found in four glioblastomas. Our results indicate that 1p deletions are common anaplastic astrocytomas and glioblastomas but are distinct from the 1p abnormalities in oligodendrogliomas.     

Histopathological malignant progression of grade II and III gliomas correlated with IDH1/2 mutation status

The impact of isocitrate dehydrogenase (IDH1/2) mutations on the malignant progression of gliomas was investigated by comparing the histopathological features of 53 grade II and III gliomas after recurrence according to the IDH1/2 status. We identified IDH1/2 mutations in 44.4?% (16 of 36) of astrocytic tumors and 70.6?% (12 of 17) of oligodendroglial tumors. Histopathological malignant progression was observed in 68.8?% (11 in 16) and 55?% (11 in 20) of astrocytic tumors with and without IDH1/2 mutations, respectively. There were 8 secondary glioblastomas (GBM) that had progressed from 5 diffuse astrocytomas (DA) and 3 anaplastic astrocytomas (AA) with IDH1/2 mutations. Seven secondary GBMs were derived from 3 DAs and 4 AAs with wild-type IDH1/2. Malignant progression was observed in 47.1?% (8 of 17) of oligodendroglial tumors. All 12 oligodendroglial tumors with IDH1/2 mutations remained as such without progressing to GBM, whereas 3 of the 5 oligodendroglial tumors without IDH1/2 mutations progressed to GBM at recurrence. In conclusion, grade II and III gliomas developed to more malignant histological types, irrespective of the IDH1/2 mutation status, and the monitoring of the IDH1/2 status could be of value to predict the development of GBM in patients with oligodendroglial tumors.     

Genomic alterations in low-grade,anaplastic astrocytomas and glioblastomas

To extend our understanding of potential stepwise genetic alterations that may underlie tumor progression from low-grade astrocytomas to glioblastomas, histopathologic and comparative genomic hybridization analyses were performed on tumor specimens from 68 primary lesions, including 40 glioblastomas, 10 anaplastic and 18 low-grade astrocytomas. The number of aberrations per case increased towards the higher grade tumors (grade II: 1.66±1.49; grade III: 2.80±1.68; grade IV: 3.02±1.07; F=6.955, p=0.002). A gain of 7/7q was common and the most frequently seen aberration in low-grade astrocytomas, whereas loss of 10q was the most frequently seen anomaly in anaplastic astrocytomas and glioblastomas. Chromosome 7p amplification was only detected in glioblastomas. Chromosome 10/10q deletion and combination of lp, 19q and 17p deletions were specific to high-grade astrocytic tumors. Sequences of chromosome 7 and 10 seem to have pivotal roles in the biology of human gliomas. The genomic copy deletions of chromosomes lp and 19q might provide an alternative mechanism in the genesis of astrocytomas.     

Genetic alterations and signaling pathways in the evolution of gliomas

Gliomas are the most common primary brain tumors. They account for more than 70% of all neoplasms of the central nervous system and vary considerably in morphology, location, genetic alterations, and response to therapy. Most frequent and malignant are glioblastomas. The vast majority (>90%) develops rapidly after a short clinical history and without evidence of a less malignant precursor lesion (primary or de novo glioblastoma). Secondary glioblastomas develop more slowly through progression from low-grade or anaplastic astrocytoma. These glioblastoma subtypes constitute distinct disease entities that affect patients of different age, develop through distinct genetic pathways, show different RNA and protein expression profiles, and may differ in their response to radio- and chemotherapy. Recently, isocitrate dehydrogenase 1 ( IDH1 ) mutations have been identified as a very early and frequent genetic alteration in the pathway to secondary glioblastomas as well as that in oligodendroglial tumors, providing the first evidence that low-grade astrocytomas and oligodendrogliomas may share common cells of origin. In contrast, primary glioblastomas very rarely contain IDH1 mutations, suggesting that primary and secondary glioblastomas may originate from different progenitor cells, despite the fact that they are histologically largely indistinguishable. In this review, we summarize the current status of genetic alterations and signaling pathways operative in the evolution of astrocytic and oligodendroglial tumors. ( Cancer Sci 2009; 100 2235–2241)     

Cytochrome P450 1B1 expression in glial cell tumors: an immunotherapeutic target.

PURPOSE: Among central nervous system malignancies, cytochrome P450 1B1 (CYP1B1) expression has only been characterized in medulloblastoma. An immunotherapeutic agent targeting this antigen was shown to safely stimulate a good immune response. To evaluate the viability of further research efforts targeting this antigen, we examined the expression of CYP1B1 in glial cell malignancies. EXPERIMENTAL DESIGN: We studied the frequency and extent of CYP1B1 expression by immunohistochemical analysis in 269 glial tumors (including all major pathologic types) on a tissue microarray. Results were categorized by percentage of cells stained and intensity of cytoplasmic staining within cells. Correlation of CYP1B1 expression with patient prognosis was evaluated by univariate and multivariate analyses. RESULTS: Overall, increased CYP1B1 expression in glial tumors was associated with decreased patient survival time (P < 0.0014 for both percentage and intensity of staining). A significant difference existed in percentage and intensity of staining between astrocytic and oligodendroglial tumors (P = 0.0002 and 0.0003, respectively), between grades of tumors (P < 0.0001 and 0.0079), and between pathologic types of tumors (P < 0.0001 and 0.0339). Positive CYP1B1 staining was seen in 81% of glioblastomas, 84% of anaplastic astrocytomas, 61% of oligodendrogliomas, and 67% of anaplastic oligodendrogliomas. Paradoxically, within specific tumor pathologies, there was a trend toward increased survival as CYP1B1 expression increased. However, in the multivariate analysis, this trend disappeared, and CYP1B1 expression seemed prognostically neutral. CONCLUSION: CYP1B1 is frequently expressed in a variety of gliomas and could be used as a target for immunotherapy.     

IDH‐mutated astrocytomas with 19q‐loss constitute a subgroup that confers better prognosis

IDH‐mutant gliomas are classified into astrocytic or oligodendroglial tumors by 1p/19q status in the WHO 2016 classification, with the latter presenting with characteristic morphology and better prognosis in general. However, the morphological and genetic features within each category are varied, and there might be distinguishable subtypes. We analyzed 170 WHO grade II‐IV gliomas resected in our institution. 1p/19q status was analyzed by microsatellite analysis, and genetic mutations were analyzed by next‐generation sequencing and Sanger sequencing. For validation, the Brain Lower Grade Glioma dataset of The Cancer Genome Atlas was analyzed. Of the 42 grade III IDH‐mutated gliomas, 12 were 1p‐intact/19q‐intact (anaplastic astrocytomas [AA]), 7 were 1p‐intact/19q‐loss (AA), and 23 showed 1p/19q‐codeletion (anaplastic oligodendrogliomas). Of the 88 IDH‐wild type glioblastomas (GBMs), 14 showed 1p‐intact/19q‐loss status. All of the seven 1p‐intact/19q‐loss AAs harbored TP53 mutation, but no TERT promotor mutation. All 19q‐loss AAs had regions presenting oligodendroglioma‐like morphology, and were associated with significantly longer overall survival compared to 19q‐intact AAs (P = .001). This tendency was observed in The Cancer Genome Atlas Lower Grade Glioma dataset. In contrast, there was no difference in overall survival between the 19q‐loss GBM and 19q‐intact GBM (P = .4). In a case of 19q‐loss AA, both oligodendroglial morphology and 19q‐loss disappeared after recurrence, possibly indicating correlation between 19q‐loss and oligodendroglial morphology. We showed that there was a subgroup, although small, of IDH‐mutated astrocytomas harboring 19q‐loss that present oligodendroglial morphology, and also were associated with significantly better prognosis compared to other 19q‐intact astrocytomas.