IDH1-Associated Primary Glioblastoma in Young Adults Displays Differential Patterns of Tumour and Vascular Morphology

Glioblastoma is a highly aggressive tumour with marked heterogeneity at the morphological level in both the tumour cells and the associated highly prominent vasculature. As we begin to develop an increased biological insight into the underlying processes driving the disease, fewer attempts have thus far been made to understand these phenotypic differences. We sought to address this by carefully assessing the morphological characteristics of both the tumour cells and the associated vasculature, relating these observations to the IDH1/MGMT status, with a particular focus on the early onset population of young adults who develop primary glioblastoma. 276 primary glioblastoma specimens were classified into their predominant cell morphological type (fibrillary, gemistocytic, giant cell, small cell, oligodendroglial, sarcomatous), and assessed for specific tumour (cellularity, necrosis, palisades) and vascular features (glomeruloid structures, arcades, pericyte proliferation). IDH1 positive glioblastomas were associated with a younger age at diagnosis, better clinical outcome, prominent oligodendroglial and small cell tumour cell morphology, pallisading necrosis and glomeruloid vascular proliferation in the absence of arcade-like structures. These features widen the phenotype of IDH1 mutation-positive primary glioblastoma in young adults and provide correlative evidence for a functional role of mutant IDH1 in the differential nature of neo-angiogenesis in different subtypes of glioblastoma

Receptor Tyrosine Kinase Genes Amplified in Glioblastoma Exhibit a Mutual Exclusivity in Variable Proportions Reflective of Individual Tumor Heterogeneity

Intratumoral heterogeneity in human solid tumors represents a major barrier for the development of effective molecular treatment strategies, as treatment efficacies will reflect the molecular variegation in individual tumors. In glioblastoma, the generation of composite genomic profiles from bulk tumor samples has allowed one to map the genomic amplifications of putative genetic drivers and to prioritize therapeutic targeting strategies aimed at eradicating the tumor burden. Notably, amplification of multiple receptor tyrosine kinases (RTK) within a single tumor specimen obtained from patients is frequently observed. In this study, use of a detailed multicolor FISH mapping procedure in pathologic specimens revealed a mutual exclusivity of gene amplification in the majority of glioblastoma tumors examined. In particular, the two most commonly amplified RTK genes, EGFR and PDGFRA, were found to be present in variable proportions across the tumors, with one or the other gene predominating in certain areas of the same specimen. Our findings have profound implications for designing efficacious therapeutic regimens, as it remains unclear that how the cells with different gene amplification events contribute to disease propagation or the response to molecular targeted therapies. Cancer Res; 72(7); 1614-20. (C)2012 AACR

Distinct Phenotypic Differences Associated with Differential Amplification of Receptor Tyrosine Kinase Genes at 4q12 in Glioblastoma

Gene amplification at chromosome 4q12 is a common alteration in human high grade gliomas including glioblastoma, a CNS tumour with consistently poor prognosis. This locus harbours the known oncogenes encoding the receptor tyrosine kinases PDGFRA, KIT, and VEGFR2. These receptors are potential targets for novel therapeutic intervention in these diseases, with expression noted in tumour cells and/or associated vasculature. Despite this, a detailed assessment of their relative contributions to different high grade glioma histologies and the underlying heterogeneity within glioblastoma has been lacking. We studied 342 primary high grade gliomas for individual gene amplification using specific FISH probes, as well as receptor expression in the tumour and endothelial cells by immunohistochemistry, and correlated our findings with specific tumour cell morphological types and patterns of vasculature. We identified amplicons which encompassed PDGFRA only, PDGFRA/KIT, and PDGFRA/KIT/VEGFR2, with distinct phenotypic correlates. Within glioblastoma specimens, PDGFRA amplification alone was linked to oligodendroglial, small cell and sarcomatous tumour cell morphologies, and rare MGMT promoter methylation. A younger age at diagnosis and better clinical outcome in glioblastoma patients is only seen when PDGFRA and KIT are co-amplified. IDH1 mutation was only found when all three genes are amplified; this is a subgroup which also harbours extensive MGMT promoter methylation. Whilst PDGFRA amplification was tightly linked to tumour expression of the receptor, this was not the case for KIT or VEGFR2. Thus we have identified differential patterns of gene amplification and expression of RTKs at the 4q12 locus to be associated with specific phenotypes which may reflect their distinct underlying mechanisms

Receptor Tyrosine Kinase Genes Amplified in Glioblastoma Exhibit a Mutual Exclusivity in Variable Proportions Reflective of Individual Tumor Heterogeneity

Intratumoral heterogeneity in human solid tumors represents a major barrier for the development of effective molecular treatment strategies, as treatment efficacies will reflect the molecular variegation in individual tumors. In glioblastoma, the generation of composite genomic profiles from bulk tumor samples has allowed one to map the genomic amplifications of putative genetic drivers and to prioritize therapeutic targeting strategies aimed at eradicating the tumor burden. Notably, amplification of multiple receptor tyrosine kinases (RTK) within a single tumor specimen obtained from patients is frequently observed. In this study, use of a detailed multicolor FISH mapping procedure in pathologic specimens revealed a mutual exclusivity of gene amplification in the majority of glioblastoma tumors examined. In particular, the two most commonly amplified RTK genes, EGFR and PDGFRA, were found to be present in variable proportions across the tumors, with one or the other gene predominating in certain areas of the same specimen. Our findings have profound implications for designing efficacious therapeutic regimens, as it remains unclear that how the cells with different gene amplification events contribute to disease propagation or the response to molecular targeted therapies. Cancer Res; 72(7); 1614-20. (C)2012 AACR

Distinct cell morphological types in clinical glioblastoma specimens.

<p>Examples of tumours are shown with predominant morphology classified as fibrillary (A, RMH5690, pleomorphic cells with pink cytoplasm and mitotic figures (arrows)), gemistocytic (B, RMH6716, cells with abundant glassy cytoplasm and eccentric nuclei (arrows)), giant cell (C, RMH6004, very large pleomorphic cells with hyperchromatic nuclei (arrows)), small cell (D, RMH5723, small cells with brisk mitotic activity (arrows)), oligodendroglial (E, RMH5970, ‘fried egg’ appearance of tumour cells (arrows)), and sarcomatous (F, RMH5966, disorganised fascicles of spindle cells (arrows)). All images original magnification×200, haematoxylin and eosin.</p

Expression of the chondroitin sulphate proteoglycan, NG2, in paediatric brain tumors

Monografia realizada no âmbito da unidade de Estágio Curricular do Mestrado Integrado em Ciências Farmacêuticas, apresentada à Faculdade de Farmácia da Universidade de CoimbraO sono pode ser caracterizado em cinco estadios fundamentais, que se diferenciam de acordo com o padrão do electroencefalograma (EEG) e a presença ou ausência de movimentos oculares rápidos (rapid eye moviments: REM), além de mudanças em diversas outras variáveis fisiológicas, como o tónus muscular e o padrão cardiorespiratório. Os distúrbios do sono são das queixas mais frequentemente encontradas em contexto médico e farmacêutico. Estes podem ser classificados em dissonias e parassonias, consoante a sua origem. Um estudo realizado em três farmácias do concelho de Cantanhede, que contou com 103 participantes, teve como objetivo avaliar a qualidade do sono dos utentes, bem como analisar o consumo dos medicamentos hipnóticos. Este estudo permitiu fazer observações interessantes, tais como: o número de horas que as pessoas passam deitadas, desde que vão dormir até acordar, é maior que o número de horas de sono; a grande maioria das pessoas revelou acordar várias vezes durante a noite, sendo que depois tem mais dificuldade para voltar a adormecer; os utentes mais jovens são aqueles que apresentam mais sonolência durante o dia; quase metade dos utentes acordam cansados, sendo esta percentagem maior nas mulheres; mais de metade dos utentes afirmou tomar, ou já ter tomado, algum hipnótico; os medicamentos mais consumidos são as benzodiazepinas de curta duração de ação.Sleep can be characterized into five basic stages which differ according to the pattern of electroencephalogram (EEG) and the presence or absence of rapid eye movement (rapid eye moviments: REM) in addition to other changes in various physiological variables, such as muscle tone and cardiorespiratory pattern. Sleep disorders are the complaints most often found in medical and pharmaceutical context. These can be classified into dyssomnias and parasomnias (trocar a ordem destas duas palavras), depending on the source of the disturbance. A study carried out in three pharmacies in the municipality of Cantanhede which included 103 volunteers, aimed to evaluate their sleep quality as well as to analyze the consumption of hypnotic drugs. This questionnaire allowed me to make interesting observations, such as the number of hours that people stay lying, since they go to sleep until they wake up is greater than the number of sleeping hours; the vast majority of people revealed waking several times during the night, and consequently they have more difficulty returning to sleep; the youngest users are those with more daytime sleepiness; almost half of the users wake up tired, with the higher percentage corresponding to women; more than half of users said that they are taking or have already taken some hypnotic pills; the most commonly used drugs are within the group of benzodiazepines of short duration of action

Distribution and clinical significance of predominant cell morphology in glioblastoma.

<p>(A) Pie chart showing proportion of tumours with predominant fibrillary (purple, 53.6%), gemistocytic (blue), 7.9%, giant cell (green, 3.9%), small cell (light green, 6.9%), oligodendroglial (yellow, 21.7%) and sarcomatous (orange, 5.8%) morphology. (B) Boxplot showing the age distribution of the morphological subtypes (C) Kaplan-Meier curve showing association of predominant cell morphology and clinical outcome (overall survival).</p

Association of specific vascular architecture with IDH1 status and young age.

<p>(A) Example of glomeruloid appearance of tumour vessels (arrows). Haematoxylin and eosin. (B) Tumour cell positivity for mutant IDH1 associated with glomeruloid vessels. RMH5984. (C) Contrast-enhanced T1-weighted images of patient RMH5984, showing an incompletely enhancing lesion (arrow). (D) Tumour vessels forming arcade-like structures (arrows). Haematoxylin and eosin. (E) All tumours with arcade-like vascular structures were negative for IDH1 mutation by immunohistochemistry (and direct sequencing). RMH6642. (F) Contrast-enhanced T1-weighted images of patient RMH6642, with pronounced ring-like enhancement (arrow). All histopathological images original magnification×200.</p

Differential patterns of vascularisation and necrosis.

<p>(A) Prominent vascularisation occurs around large necrotic areas of the tumour; (B) High expression of CD105 reflects active neovascularisation in these areas. RMH5967. (C) Regions with prominent pallisading necrosis were poorly vascularised; (D) Only scattered CD105-positive vessels were often observed. RMH5725 All images original magnification×100.</p