Paritosh Pandey

Novel Glioblastoma Markers with Diagnostic and Prognostic Value Identified through Transcriptome Analysis

Purpose: Current methods of classification of astrocytoma based on histopathologic methods are often subjective and less accurate. Although patients with glioblastoma have grave prognosis, significant variability in patient outcome is observed. Therefore, the aim of this study was to identify glioblastoma diagnostic and prognostic markers through microarray analysis. Experimental Design: We carried out transcriptome analysis of 25 diffusely infiltrating astrocytoma samples [WHO grade II—diffuse astrocytoma, grade III—anaplastic astrocytoma, and grade IV—glioblastoma (GBM)] using cDNA microarrays containing 18,981 genes. Several of the markers identified were also validated by real-time reverse transcription quantitative PCR and immunohistochemical analysis on an independent set of tumor samples (n = 100). Survival analysis was carried out for two markers on another independent set of retrospective cases (n = 51). Results: We identified several differentially regulated grade-specific genes. Independent validation by real-time reverse transcription quantitative PCR analysis found growth arrest and DNA-damage–inducible α (GADD45α) and follistatin-like 1 (FSTL1) to be up-regulated in most GBMs (both primary and secondary), whereas superoxide dismutase 2 and adipocyte enhancer binding protein 1 were up-regulated in the majority of primary GBM. Further, identification of the grade-specific expression of GADD45α and FSTL1 by immunohistochemical staining reinforced our findings. Analysis of retrospective GBM cases with known survival data revealed that cytoplasmic overexpression of GADD45α conferred better survival while the coexpression of FSTL1 with p53 was associated with poor survival. Conclusions: Our study reveals that GADD45α and FSTLI are GBM-specific whereas superoxide dismutase 2 and adipocyte enhancer binding protein 1 are primary GBM-specific diagnostic markers. Whereas GADD45α overexpression confers a favorable prognosis, FSTL1 overexpression is a hallmark of poor prognosis in GBM patients.

PBEF1/NAmPRTase/Visfatin: A potential malignant astrocytoma/glioblastoma serum marker with prognostic value

Malignant astrocytomas comprise anaplastic astrocytoma (AA; grade III) and Glioblastoma (GBM; grade IV). GBM is the most malignant with a median survival of 10-12 months in patients. Using cDNA microarray based expression profiling of different grades of astrocytomas, we identified several fold increased levels of PBEF1 transcripts in GBM samples. Pre-B-cell colony enhancing factor 1 gene (PBEF1) encodes Nicotinamide phosphoribosyltransferase (NAmPRTase), which catalyses the rate limiting step in the salvage pathway of NAD metabolism in mammalian cells. Further validation using real time RT-qPCR on an independent set of tumor samples (n=91) and normal brain samples (n=9), GBM specific higher expression of PBEF1 was confirmed. Immunohistochemical staining for PBEF1 on a subset of the above samples largely reinforced our finding. We carried out ELISA analysis on serum samples of astrocytoma patients to determine whether this protein levels would correlate with the presence of tumor and tumor grade. PBEF1 serum levels were substantially elevated in many of the AA and GBM patients. Statistical analysis of these data indicates that in patients with astrocytoma, serum PBEF1 levels correlate with tumor grade and is highest in GBM. Immunohistochemical analysis of an independent set of 51 retrospective GBM cases with known survival data revealed that PBEF1 expression in the tumor tissue along with its co-expression with p53 was associated with poor survival. Thus, we have identified PBEF1 as a potential malignant astrocytoma serum marker and prognostic indicator among GBMs.

miR-219-5p Inhibits Receptor Tyrosine Kinase Pathway by Targeting EGFR in Glioblastoma

Glioblastoma is one of the common types of primary brain tumors with a median survival of 12–15 months. The receptor tyrosine kinase (RTK) pathway is known to be deregulated in 88% of the patients with glioblastoma. 45% of GBM patients show amplifications and activating mutations in EGFR gene leading to the upregulation of the pathway. In the present study, we demonstrate that a brain specific miRNA, miR-219-5p, repressed EGFR by directly binding to its 3′-UTR. The expression of miR-219-5p was downregulated in glioblastoma and the overexpression of miR-219-5p in glioma cell lines inhibited the proliferation, anchorage independent growth and migration. In addition, miR-219-5p inhibited MAPK and PI3K pathways in glioma cell lines in concordance with its ability to target EGFR. The inhibitory effect of miR-219-5p on MAPK and PI3K pathways and glioma cell migration could be rescued by the overexpression of wild type EGFR and vIII mutant of EGFR (both lacking 3′-UTR and thus being insensitive to miR-219-5p) suggesting that the inhibitory effects of miR-219-5p were indeed because of its ability to target EGFR. We also found significant negative correlation between miR-219-5p levels and total as well as phosphorylated forms of EGFR in glioblastoma patient samples. This indicated that the downregulation of miR-219-5p in glioblastoma patients contribute to the increased activity of the RTK pathway by the upregulation of EGFR. Thus, we have identified and characterized miR-219-5p as the RTK regulating novel tumor suppressor miRNA in glioblastoma.

Pediatric Supratentorial Subdural Empyemas: A Retrospective Analysis of 65 Cases

Aim: Intracranial subdural empyemas (SDEs), the majority of which are supratentorial in location, are common neurosurgical emergencies in developing countries, especially in the pediatric age group. They result in significant morbidity and mortality despite improvements in neuroimaging, surgical techniques and antibiotic therapy. In the present study, we retrospectively analyze our experience with operated cases of intracranial supratentorial SDEs in the pediatric age group. Patients and Methods: 65 pediatric patients (age ≤18 years) with supratentorial SDEs were treated in our institute between January 1988 and May 2006, and the case records analyzed with respect to clinical, radiological, bacteriological and surgical complications and outcome data. Results: There was a slight male preponderance (55%), with mean age being 9.54 ± 6.43 years (range 3 months to 18 years). Otogenic source was the most common identifiable etiology, followed by postmeningitic and rhinogenic sources. The initial surgical intervention, burr holes (44 patients; 67.7%) and craniotomy (21 patients; 32.3%), varied with individual cases and surgeon preference. Initial craniotomy was associated with lesser repeat procedures, and slightly better clinical outcome. The majority (83.3%) of patients with significant residual requiring repeat surgery were found to have undergone burr hole evacuation initially. The mortality rate in the present series was 10.8%. Follow-up was available for 41 patients (70.7%) with an average follow-up of 10.4 months. 88% of patients showed good outcomes (Glasgow Outcome Scores of 4 or 5) at the latest follow-up. Conclusion: Pediatric supratentorial SDEs, although rapidly fatal if not identified promptly, can be effectively managed with early surgical drainage (preferably craniotomy), eradication of the source, and sensitive broad-spectrum antibiotics (i.v.) with good outcomes.

A Fourteen Gene GBM Prognostic Signature Identifies Association of Immune Response Pathway and Mesenchymal Subtype with High Risk Group

Background Recent research on glioblastoma (GBM) has focused on deducing gene signatures predicting prognosis. The present study evaluated the mRNA expression of selected genes and correlated with outcome to arrive at a prognostic gene signature. Methods Patients with GBM (n = 123) were prospectively recruited, treated with a uniform protocol and followed up. Expression of 175 genes in GBM tissue was determined using qRT-PCR. A supervised principal component analysis followed by derivation of gene signature was performed. Independent validation of the signature was done using TCGA data. Gene Ontology and KEGG pathway analysis was carried out among patients from TCGA cohort. Results A 14 gene signature was identified that predicted outcome in GBM. A weighted gene (WG) score was found to be an independent predictor of survival in multivariate analysis in the present cohort (HR = 2.507; B = 0.919; p<0.001) and in TCGA cohort. Risk stratification by standardized WG score classified patients into low and high risk predicting survival both in our cohort (p = <0.001) and TCGA cohort (p = 0.001). Pathway analysis using the most differentially regulated genes (n = 76) between the low and high risk groups revealed association of activated inflammatory/immune response pathways and mesenchymal subtype in the high risk group. Conclusion We have identified a 14 gene expression signature that can predict survival in GBM patients. A network analysis revealed activation of inflammatory response pathway specifically in high risk group. These findings may have implications in understanding of gliomagenesis, development of targeted therapies and selection of high risk cancer patients for alternate adjuvant therapies.

Outcome of ventriculoperitoneal shunt placement in Grade IV tubercular meningitis with hydrocephalus: a retrospective analysis in 95 patients. Clinical article.

OBJECT Hydrocephalus is the most common complication of tubercular meningitis (TBM). Relieving hydrocephalus by ventriculoperitoneal (VP) shunt placement has been considered beneficial in patients in Palur Grade II or III. The role of VP shunt placement in those of Grade IV is controversial and the general tendency is to avoid its use. Some authors have suggested that patients in Grade IV should receive a shunt only if their condition improves with a trial placement of an external ventricular drain (EVD). In the present study, the authors assessed the outcome of VP shunt placement in patients in Grade IV TBM with hydrocephalus to examine the factors predicting outcome and to determine whether a trial with an EVD is absolutely necessary prior to shunt placement. METHODS Ninety-five consecutive cases of TBM with hydrocephalus in which the patients underwent VP shunt placement were retrospectively analyzed, and direct VP shunts were placed whenever possible. An EVD was placed first only in the presence of deranged blood parameters. Outcomes were assessed both in the short and long term. RESULTS The mean patient age was 17.5 years (range 1-55 years). Fifty-two patients underwent direct VP shunt placement, and the remaining 43 received EVDs first. Overall, 33 and 45% of patients had favorable short- and long-term outcomes, respectively. Age older than 3 years and duration of altered sensorium < or = 3 days were predictive of a favorable short-term outcome. Glasgow Coma Scale score at presentation was predictive of long-term outcome. Of the patients who did not improve with placement of an EVD prior to VP shunt insertion, 24 and 18% had favorable short- and long-term outcomes, respectively; this was not significantly different from the outcome in the patients who underwent direct VP shunt placement. CONCLUSIONS Direct VP shunt placement is an effective option in patients with Grade IV TBM with hydrocephalus. Age and duration of altered sensorium are predictive of short-term outcome, while Glasgow Coma Scale score at presentation predicts long-term outcome. Ventriculoperitoneal shunts should be considered even in patients who do not improve with an EVD.

Remote supratentorial extradural hematoma following posterior fossa surgery

IntroductionPosterior fossa tumors are associated frequently with hydrocephalus. Remote supratentorial hematoma after posterior fossa surgery is a rare but dreaded complication.DiscussionThese hematomas can be intraparenchymal or extradural. The possible causes include sudden decompression of ventricular pressure in the supratentorial compartment, rupture of cortical veins in the sitting position, coagulopathy, hemodynamic fluctuations during surgery, and position-related ischemia. We report a large bifrontal extradural hematoma following posterior fossa surgery for a vermian medulloblastoma.

Cerebellar abscesses in children: excision or aspiration?

OBJECT Cerebellar abscesses are common neurosurgical emergencies in developing countries, and have a distressingly high mortality rate of 10 to 15% even today. There is still no consensus on the standard approach to these lesions, and controversy persists over whether these lesions should be treated with primary excision or aspiration. METHODS The authors retrospectively analyzed 82 cases of cerebellar pyogenic abscesses in children treated at their institution over a period of 10 years. This represents the largest such series being described in literature. All lesions except 1 were otogenic in origin. The clinical and radiological features are discussed. RESULTS Primary excision was undertaken in 66 patients (80%) and aspiration in 16 patients (20%). Five patients in whom the abscesses were initially treated with aspiration subsequently underwent elective excision. Nine (12.6%) of 71 patients in whom the abscesses were excised had residual abscesses on postoperative imaging; in those who had undergone aspiration as the primary treatment, 6 (54.5%) of 11 patients had recurrent abscesses. There were no deaths among the patients who underwent excision of the abscess. Also, excision of posterior fossa abscesses required fewer repeated procedures with lower recurrence rates, and statistically lower rate of complications. CONCLUSIONS Compared to primary aspiration, the authors found that primary excision is the preferred method for treating cerebellar abscesses.

Focal intradural brain infections in children: an analysis of management and outcome.

Introduction: Focal intradural infections of the brain include empyema and abscess in the supratentorial and infratentorial spaces. These are amenable to surgical management. Various other issues may complicate the course of management, e.g. hydrocephalus with infratentorial lesions or cortical venous thrombosis with supratentorial lesions. Here, we review the management and identify factors affecting outcome in these patients. Materials and Methods: This is a retrospective analysis of all children (aged <18 years) treated at the National Institute of Mental Health and Neurosciences, Bangalore, India, between 1988 and 2004. Case records were analyzed to obtain clinical, radiological, bacteriological and follow-up data. Results: There were 231 children who underwent treatment for focal intradural abscess/empyema at our institute. These included 57 children with cerebral abscess, 65 with supratentorial empyema, 82 with cerebellar abscess and 27 with infratentorial empyema. All patients underwent emergency surgery (which was either burr hole and aspiration of the lesion or craniotomy/craniectomy and excision/evacuation), along with antibiotic therapy, typically 2 weeks of intravenous and 4 weeks of oral therapy. The antibiotic regimen was empiric to begin with and was altered if any sensitivity pattern of the causative organism(s) could be established by culture. Hydrocephalus was managed with external ventricular drainage initially and with ventriculoperitoneal shunt if warranted. Mortality rates were 4.8% for cerebral abscess, 9.6% for cerebellar abscess, 10.8% for supratentorial subdural empyema and 3.7% for posterior fossa subdural empyema. The choice of surgery was found to have a strong bearing on the recurrence rates and outcome in most groups, with aggressive surgery with craniotomy leading to excellent outcomes with a low incidence of residual/recurrent lesions. Conclusions: Antibiotic therapy, emergency surgery and management of associated complications are the mainstays of treatment of these lesions. We strongly advocate early, aggressive surgery with antibiotic therapy in children with focal intradural infections.

Lack of IDH1 mutation in astroblastomas suggests putative origin from ependymoglial cells

Astroblastomas are extremely rare neuroepithelial tumors of uncertain histogenesis, affecting children and young adults, and constitute a new addition to the WHO 2000 classification of CNS tumors. We report the largest series of nine cases diagnosed in a single institute over the last 13 years and review published literature. Mean age at presentation was 12.8 years (range: 22 months to 27years). Seven out of nine cases were supratentorial (frontal/frontoparietal – three, parieto‐occipital – three, parafalcine – one), one was intraventricular and another was optochaismatic/suprasellar. Five cases were high grade (anaplastic) astroblastomas with Ki‐67 labeling index of 8–10%. Immunohistochemical and ultrastructural evidence suggesting origin from cells intermediate between ependymocytes and astrocytes is presented. The histogenetic origin of these tumors remains speculative. But the lack of Isocitrate dehydrogenase 1 (IDH1) mutation as detected by immunohistochemistry in this study, which is similar to ependymomas supports putative origin from ependymoglial cells. Out of the nine cases, recurrence was noted in one case, 12 months after gross total resection with progression to high grade in the recurrent tumor. There is no recommended treatment protocol due to the rarity of this entity and prognostic factors are yet to be established.