Localisation of eloquent cortex using magnetoencephalography and its clinical implications.

OBJECTIVES: This study aimed to localise the eloquent cortex and measure evoked field (EF) parameters using magnetoencephalography in patients with epilepsy and tumours near the eloquent cortex. METHODS: A total of 41 patients (26 with drug-refractory epilepsy and 15 with tumours), with a mean age of 33 years, were recruited. Visual evoked field (VEF), auditory evoked field (AEF), sensory evoked field (SSEF), and motor-evoked field (MEF) latencies, amplitudes, and localisation were compared with those of a control population. Subgroup analyses were performed based on lobar involvement. Evoked Field parameters on the affected side were compared with those on the opposite side. The effect of distance from the lesion on nearby and distant evoked fields was evaluated. RESULTS: AEF and VEF amplitudes and latencies were reduced bilaterally (p < 0.05). Amplitude in the ipsilateral SSEF was reduced by 29.27% and 2.16% in the AEF group compared to the contralateral side (p = 0.02). In patients with temporal lobe lesions, the SSEF amplitude was reduced bilaterally (p < 0.02), and latency was prolonged compared with controls. The MEF amplitude was reduced and latency was prolonged in patients with frontal lobe lesions (p = 0.01). EF displacement was 32%, 57%, 21%, and 16% for AEF, MEF, VEF, and SSEF respectively. Patients in the epilepsy group had distant EF abnormalities. CONCLUSIONS: EF amplitude was reduced and latency was prolonged in the involved hemisphere. Distant EF amplitudes were more affected than latencies in epilepsy. Amplitude and distance from the lesion had negative correlation for all EF. EF changes indicated eloquent cortical displacement which may not be apparent on MRI.

Maternal embryonal leucine zipper kinase immunoreactivity in atypical teratoid/rhabdoid tumors: a study of 50 cases.

Atypical teratoid/rhabdoid tumors (AT/RTs) are aggressive embryonal neoplasms of the central nervous system that correspond to WHO grade IV and have a dismal prognosis. The latest Central Brain Tumor Registry of the United States data shows that AT/RT constitutes 16.6% of all embryonal tumors in children. The molecular hallmark of this tumor is pathogenic SMARCB1 genetic alterations resulting in the loss of INI-1 immunopositivity, with fewer tumors harboring SMARCA4 (BRG1) variants. Maternal embryonal leucine zipper kinase (MELK) is a member of the Snf1/AMPK family of serine/threonine-protein kinases involved in various processes such as cell cycle regulation, self-renewal of stem cells, apoptosis, and splicing regulation. Recent studies have highlighted the involvement of MELK in AT/RT and its possible therapeutic role. The purpose of this study was to review the histological and immunohistochemical profile of AT/RT with special reference to MELK  staining. In this retrospective study conducted over 6 years, all diagnosed cases of AT/RT, defined by loss of INI-1 immunopositivity, were retrieved and studied. Demographic details of patients and microscopic findings were analyzed, with special attention to histological patterns and immunohistochemistry profile including MELK immunoreactivity. There were 50 cases of AT/RT diagnosed in the specified period. Of the cases operated at our institute during this period, embryonal tumors constituted 20.6% of all pediatric brain tumors with AT/RT representing 12.6% of this subset. The median age at presentation was 3.5 years (range: 8 months-22 years) and there were three adult cases. Males outnumbered females by a ratio of 1.94:1. Tumor location was distributed equally between the supratentorial and infratentorial compartments. Characteristic rhabdoid cells were identified in 70% of cases. Areas with epithelial, mesenchymal, and undifferentiated tumor cells were seen in 8%, 20%, and 52% of cases, respectively. Cells with vacuolated cytoplasm were noted in 28% of cases. Immunohistochemistry (IHC) showed a polyimmunophenotypic profile with immunopositivity for GFAP in 70%, Vimentin in 100%, SMA in 68%, and EMA in 88% of cases, indicating the remarkable heterogeneity of the tumor cells. MELK immunopositivity was noted in 83.33% of cases. Thus, atypical teratoid/rhabdoid tumors are rare neoplasms. In line with other studies, we show that these tumors occur predominantly in very young children and display marked variability on histology and IHC with loss of INI-1. MELK is presumed to be an important molecule involved in cell cycle regulation, proliferation, and other critical functions. High expression of MELK in AT/RT may suggest its plausible role in neoplastic transformation of embryonic and postnatal multipotent neural progenitors which in turn could explain the diverse morphological and immunohistochemical characteristics observed in these tumors.

Audiovestibular findings in a 6 year old child with pilocytic astrocytoma - a case report.

Objective: Pilocytic astrocytoma commonly occurs in children and depending on the extension of the lesion may cause varied audiovestibular dysfunctions. However, audiovestibular findings are scarcely reported in the literature.Design: Audiovestibular testing was performed on a single subject on two occasions pre-surgically.Study sample: A 6 year old girl with pilocytic astrocytoma.Results: All audiological tests revealed normal findings except for the cervical vestibular evoked myogenic potential testing (cVEMP). The amplitude of cVEMP was higher in the lesion side indicating a hypersensitive vestibulocollic reflex pathway functioning.Conclusions: This case study reported a unique finding of hypersensitive cVEMP findings in the lesion side in a patient with pilocytic astrocytoma. The pathophysiological basis for this hypersensitivity is attributed to anatomical connections between the cerebellum and the vestibular nuclei through the inferior cerebellar peduncle.

Transcriptome profiling reveals PDZ binding kinase as a novel biomarker in peritumoral brain zone of glioblastoma.

PURPOSE: Peritumoural brain zone (PT) of glioblastoma (GBM) is the area where tumour recurrence is often observed. We aimed to identify differentially regulated genes between tumour core (TC) and PT to understand the underlying molecular characteristics of infiltrating tumour cells in PT. METHODS: 17 each histologically characterised TC and PT tissues of GBM along with eight control tissues were subjected to cDNA Microarray. PT tissues contained 25-30% infiltrating tumour cells. Data was analysed using R Bioconductor software. Shortlisted genes were validated using qRT-PCR. Expression of one selected candidate gene, PDZ Binding Kinase (PBK) was correlated with patient survival, tumour recurrence and functionally characterized in vitro using gene knock-down approach. RESULTS: Unsupervised hierarchical clustering showed that TC and PT have distinct gene expression profiles compared to controls. Further, comparing TC with PT, we observed a significant overlap in gene expression profile in both, despite PT having fewer infiltrating tumour cells. qRT-PCR for 13 selected genes validated the microarray data. Expression of PBK was higher in PT as compared to TC and recurrent when compared to newly diagnosed GBM tumours. PBK knock-down showed a significant reduction in cell proliferation, migration and invasion with increase in sensitivity to radiation and Temozolomide treatment. CONCLUSIONS: We show that several genes of TC are expressed even in PT contributing to the vulnerability of PT for tumour recurrence. PBK is identified as a novel gene up-regulated in PT of GBM with a strong role in conferring aggressiveness, including radio-chemoresistance, thus contributing to recurrence in GBM tumours.

H3K27M, IDH1, and ATRX expression in pediatric GBM and their clinical and prognostic significance.

PURPOSE: Pediatric glioblastoma (pGBM) tumors have been identified as an entity distinct and different from the adult variety of GBM not only with respect to pathogenesis, genetics, and molecular alterations but also in clinical outcomes and overall survival. This study aims to evaluate the immunohistochemical profile of molecular markers in pediatric GBM and correlate them with clinical features and prognosis. MATERIALS AND METHODS: We retrospectively analyzed 29 pGBMs (age range 3 to 18 years), operated at our institute between 2009 and 2014, and evaluated their clinical and histopathological features along with the immunohistochemical expression of clinically relevant molecular markers: H3K27M, p53, ATRX, and IDH1 (R132H), and correlated their expression with clinical features. We further assessed the prognostic value of these markers in our cohort of patients. RESULTS: The median overall survival (OS) of the cohort was 6.00 ± 0.882 months. The mean overall survival was 7.571 ± 1.118 months which was lower than in most studies. Preoperative Karnofsky Performance Score (KPS), extent of surgical resection, and adjuvant radiotherapy were found to be the clinical factors strongly influencing median survival (p < 0.05). Loss of ATRX expression was predominantly noted in hemispheric tumors (84%), while p53 staining was maximum in thalamic tumors (8 out of 9 cases). H3K27M mutant protein expression was noted in 8/9 thalamic tumors and 5/7 tumors in the brain stem-cerebellar-peduncular region. Patients with tumors showing H3K27M immunopositivity had the worst prognosis with a mean OS of 5 months ± 0.832 months, as against patients with H3K27M-immunonegative tumors, which was 10.143 ± 1.866 months(p = 0.006). Other markers like p53, ATRX, and IDH1 did not influence the prognosis in this patient cohort. ATRX loss of expression was associated with a better OS, with a trend to significance, and such an association has not been reported earlier. CONCLUSIONS: Ours is one among the few studies from India describing the clinical parameters and evaluating the key immunohistochemical markers in pGBM and deriving their prognostic significance. The study reiterates the poor prognostic significance of H3K27M immunopositivity.

Epilepsy surgery for focal cortical dysplasia: Seizure and quality of life (QOLIE-89) outcomes.

AIM: Surgery for drug resistant epilepsy (DRE) with focal cortical dysplasia (FCD) often requires multiple non-invasive as well as invasive pre-surgical evaluations and innovative surgical strategies. There is limited data regarding surgical management of people with FCD as the underlying substrate for DRE among the low and middle-income countries (LAMIC) including India. METHODOLOGY: The presurgical evaluation, surgical strategy and outcome of 52 people who underwent resective surgery for DRE with FCD between January 2008 and December 2016 were analyzed. The 2011 classification proposed by Blumcke et al., was used for histo-pathological categorization. The Engel classification was used for defining the seizure outcome. The surgical outcome was correlated with the preoperative clinical presentation, video encephalogram (VEEG) recording, magnetic resonance imaging (MRI), invasive monitoring, surgical findings as well as histopathology and the quality of life in epilepsy (QOLIE)- 89 scores. RESULTS: Fifty-two patients underwent resective surgery for FCD (mean age at onset of seizure: 7.94 ± 6.23 years; duration of seizures prior to surgery: 12.95 ± 9.56 years; and, age at surgery: 20.88 ± 12.51 years). The following regional distribution was found; temporal-24 (language-13), frontal-15 (motor cortex- 5), parietal-5 (sensory cortex-4), occipital-1 and multilobar-7. Forty-seven percent of the cases had FCD in the right hemisphere and 53% had FCD in the left hemisphere. Invasive monitoring was performed for identification of the epileptogenic zone (EZ) as well as eloquent cortex in 7 cases and an intra-operative electro-corticography (ECoG) was used in 32 cases. Histopathology revealed the following distribution; FCD IA-4, IB- 1, IC-5, IIA-8, IIB-18, IIIA-13, IIIB -1, IIIC-1 and IIID-1. After a median follow up of 3.7 years after surgery, 84% of patients had Engel's Ia outcome. QOLIE-89 scores improved from 38.33 ± 4.7 (31.14-49.03) before surgery to 75.21 ± 8.44 (56.49-90.49) after surgery (P < 0.001). The younger age of the patient (<20 years) at surgery (P = 0.013), a lower pre-operative score (<9) on seizure severity scale (P = 0.012), focal discharges without propagation on ictal VEEG (P < 0.001), absence of acute post-operative seizures (P < 0.001) and Type II FCD (P = 0.045) were the significant predictors for a favorable seizure outcome. CONCLUSION: Surgical management of people with DRE and FCD is possible in countries with limited resources. Meticulous pre-surgical evaluation to localize the epileptogenic zone and complete resection of the focus and lesion can lead to the cure or control of epilepsy; and, improvement in the quality of life was observed along with seizure-free outcome.

Unusual Occurrence of Multifocal Desmoplastic Infantile Astrocytoma: A Case Report and Review of the Literature.

Desmoplastic infantile gliomas are rare, benign tumors of the early infancy period. Two histological subtypes - desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma - have been described. The characteristic features of DIAs are lobar location, glial histology, and excellent prognosis after complete surgical excision. DIAs usually present as solitary, cortical-surfacing, solid-cystic neoplasms; however, atypical, aggressive, and multifocal variants of DIA have been reported in the literature. These rare DIAs presenting with multiple lesions pose a diagnostic as well as a therapeutic dilemma. We report an unusual case of an 8-month-old female infant diagnosed with multifocal (cranial and spinal) DIA and obstructive hydrocephalus and discuss the radiological and histological features of this rare variant of DIA. The patient underwent ventriculoperitoneal shunt placement to relieve the hydrocephalus, excisional biopsy from a surfacing lesion in the right frontal lobe, and multiple cycles of chemotherapy; however, the lesions continued to progress, and the patient is likely to have an unfavorable outcome.

Giant Hypothalamic Hamartoma in an Infant: A Case Report and Review of the Literature.

Giant hypothalamic hamartomas (GHH) are extremely rare lesions in infants and usually intrinsically epileptogenic. We present the case of a 10-month-old girl child presenting with drug-resistant seizures and a giant hypothalamic lesion that was confirmed as hamartoma on histopathology. Surgical decompression and disconnection from the hypothalamus was performed with the intent of controlling her seizures. Unfortunately, the patient developed right middle cerebral artery and posterior cerebral artery territory infarction, possibly due to vasospasm or thrombosis of the vessels. The patient had a stormy postoperative course but has recovered well neurologically at the 18-month follow-up. Histopathological examination revealed abnormal clusters of NeuN-positive neurons, which was confirmatory of hypothalamic hamartoma. A review of the published literature on infantile GHH, its management and the postoperative complications is undertaken in this short report.

Evolution of MRI changes in Rasmussen's encephalitis.

PURPOSE: We studied the MRI findings in 16 patients with Rasmussen's encephalitis (RE), further analysed serial MRI changes in 11 of them and correlated it with clinical features. METHODOLOGY: The diagnosis of RE was based on the European consensus statement (Brain, 128, 2005, 454). Details related to demographical, clinical, MRI observations were analysed. RESULTS: Forty MRIs of brain of 16 patients were reviewed. Eleven patients had undergone serial brain MRIs ranging from two to five occasions. All the patients had unihemispheric focal cortical atrophy, predominantly in the perisylvian region (n = 13). Other features were white matter signal changes (n = 14), and ipsilateral caudate (n = 6) and putamen (n = 4) atrophy. Signal alterations in putamen and caudate were noted in four each. In all the 11 patients with serial MRI, there was progression of cerebral atrophy and a trend towards increase in MRI staging. The MRI signal changes remained same in five patients, resolved in three patients, differential change in two patients and increased in one patient. Diffusion-weighted imaging showed facilitated diffusion (n = 5), and MR spectroscopy showed reduced N-acetyl-aspartate and elevated lactate (n = 2). CONCLUSIONS: Pattern recognition of MRI findings and the changes in serial MRI might serve as a surrogate marker of disease viz. unihemispheric progressive focal cortical atrophy and signal changes predominantly in the perisylvian distribution and caudate followed by putamen involvement. This might assist in understanding and monitoring of the disease progression.

Central nervous system lymphoma: patterns of incidence in Indian population and effect of steroids on stereotactic biopsy yield.

BACKGROUND: Epidemiology of primary central nervous system lymphoma (PCNSL) world-wide shows an increase in incidence linked to human immunodeficiency virus (HIV) pandemic. MATERIALS AND METHODS: This retrospective review of case records analyzed the trends of hospital-based incidence of PCNSL over two decades (1991-2010), relation to immune status and effect of steroids on yield of stereotactic biopsy (STB). RESULTS: A total of 76 cases of PCNSL were diagnosed over a period of two decades. Incidence of lymphomas amongst all biopsied lesions showed a gradual increase from 0.18% at the beginning of study period to 0.41% at the end of study period. Only 8.6% (3 of 35 tested) of the PCNSL patients were positive for HIV. The mean age of patients with HIV infection (31.3 ± 3.5 years) was significantly lower compared with those without HIV infection (44.7 ± 10.9 years) (P = 0.033). Diagnosis was obtained by open biopsy in 32 patients (42.1%) and STB in 44 patients (57.9%). Open biopsy yielded a histological confirmation of PCNSL in all cases. Among those who underwent STB, the incidence of negative biopsy with short duration of steroids (≤ 1 week) was 33.3% and increased to 57.1% with increasing duration of steroid treatment (>1 week). CONCLUSIONS: This study documented an increase in hospital based incidence of PCNSL in our institute, independent of HIV association. Steroid intake administration for more than a week prior to biopsy adversely affected the yield of STB in PCNSL.

Higher topoisomerase 2 alpha gene transcript levels predict better prognosis in GBM patients receiving temozolomide chemotherapy: identification of temozolomide as a TOP2A inhibitor.

The search for molecular markers which predict response to chemotherapy is an important aspect of current neuro-oncology research. MGMT promoter methylation is the only proved marker of glioblastoma. The purpose of this study was to assess the effect of topoisomerase expression on glioblastoma survival and study the mechanisms involved. The transcript levels of all isoforms of the topoisomerase family in all grades of diffuse astrocytoma were assessed. A prospective study of patients with glioblastoma treated by a uniform treatment procedure was performed with the objective of correlating outcome with gene expression. The ability of TOP2A enzyme to relax the super coiled plasmid DNA in the presence of temozolomide was evaluated to assess its effect on TOP2A. The temozolomide cyctotoxicity of TOP2A-silenced U251 cells was assessed. The transcript levels of TOP2A, TOP2B, and TOP3A are upregulated significantly in GBM in comparison with lower grades of astrocytoma and normal brain samples. mRNA levels of TOP2A correlated significantly with survival of the patients. Higher TOP2A transcript levels in GBM patients predicted better prognosis (P = 0.043; HR = 0.889). Interestingly, we noted that temozolomide inhibited TOP2A activity in in-vitro enzyme assays. We also noted that siRNA knock down of TOP2A rendered a glioma cell line resistant to temozolomide chemotherapy. We demonstrated for the first time that temozolomide is also a TOP2A inhibitor and established that TOP2A transcript levels determine the chemosensitivity of glioblastoma to temozolomide therapy. Very high levels of TOP2A are a good prognostic indicator in GBM patients receiving temozolomide chemotherapy.

Differential expression of a novel voltage gated potassium channel--Kv 1.5 in astrocytomas and its impact on prognosis in glioblastoma.

INTRODUCTION: Ion channels are subjects of intense research, due to their easy access and potential for being drug targets. Kv1.5 is a voltage gated potassium channel, earlier thought to be cardiac specific. Recent studies have revealed that K(+) channels play an important role in apoptosis, glial cell proliferation and biology of various cancers. No study has so far been performed to assess their expression in astrocytomas and correlate its impact on the clinical behaviour of gliomas. METHODS: Sixty samples of astrocytoma which included 9 diffuse astrocytoma (DA) grade II, 11 anaplastic astrocytoma (AA) grade III and 40 glioblastoma (GBM), along with normal brain tissue (cerebral cortex; n = 5) were analysed for their Kv1.5 protein expression. Immunohistochemical expression of Kv1.5 in various grades was assessed semi quantitatively. The patients with GBM (n = 40) were treated with uniform protocol and their survival was documented. RESULTS: The mean expression of Kv1.5 in DA, AA and GBM was 22.2 ± 9.71%, 11.81 ± 12.3% and 10.37 ± 11.05%, respectively, the difference being statistically significant (p = 0.004). The mean expression in low grade astrocytoma (WHO II) was significantly higher than higher grades (22.2% and 10.7%; p = 0.005). On analysing the influence of Kv1.5 expression on survival of GBM patients, we noted that increasing Kv1.5 labelling index (LI) correlated with a favourable prognosis, albeit not being significant (p = 0.310; HR = 0.901). CONCLUSIONS: Kv1.5 expression occurs more in DA, when compared to high grade astrocytoma. GBM patients with higher Kv1.5 expression had better survival, though not reaching statistical significance.

Evaluating the Role of Perilesional Tissue in Pathobiology of Epileptogenesis of Vascular Malformations of the Central Nervous System.

Background and Purpose: Seizures are common presentation of cerebral vascular malformation (CVM). Topography and haemodynamic alterations are proposed as mechanisms for epileptogenesis, but the role of glial/neuronal alterations in perilesional tissue has not received much attention. Identification of the exact pathophysiologic basis could have therapeutic implications. To evaluate whether angioarchitectural factors of CVM or alterations in neuroglial/stroma of the adjacent cortex contribute to seizures. Method: The clinical, imaging and histological characteristics of arteriovenous malformation (AVM) and cerebral cavernous malformation (CCM) with and without seizures was evaluated using neuroimaging imaging and digital subtraction angiography parameters and histopathology by morphology and immunohistochemistry. Results: Fifty-six cases of CVM were diagnosed over a 2-year study period. Of these, 32 had adequate perilesional tissue for evaluation (AVM, 24; CCM, 8). Seizures at presentation was seen in 12/24 (50%) of AVM and 5/8 (62.5%) CCM. In AVM, hemosiderin deposition and gliosis in parenchyma (p=0.01) had significant association with seizure. Siderotic vessels in the adjacent cortex was exclusively seen only in CCM with seizures (p=0.018). Angioarchitectural features of CVM on imaging and neuronal alterations in adjacent cortex on histology failed to show any statistically significant difference between the two groups (p>0.05). Conclusions: We propose that changes in adjacent cortex appear to be epileptogenic rather than the malformation per se. Reactive gliosis and hemosiderin deposits in perilesional tissue in AVM and siderotic vessels in CCM were associated with seizure. This explains the better outcomes following extended lesionectomy that includes epileptogenic perilesional tissues.

Rasmussen's encephalitis: Imaging spectrum on simultaneous FDG-PET and MRI imaging correlation.

Rasmussen encephalitis (RE) is a rare, chronic, idiopathic, progressive, inflammatory, neurodegenerative disease process and typically seen in pediatric cohort. Although primarily a disease affecting children, adult cases with RE have also been reported. It manifests as drug refractory epilepsia partialis continua (EPC). Immunomodulation, although delays progression of disease, seldom influences outcome. Imaging is crucial for early diagnosis, and monitoring disease progression. Magnetic resonance imaging (MRI) is mainstay of imaging with nuclear imaging being a complimentary tool for diagnosing RE. Typical imaging features of RE on MRI are hemispherical atrophy, caudate nucleus atrophy, ex vacuo dilatation of the ventricular system and sulci. We review 5 cases of RE who fulfilled diagnostic criteria proposed by Bien et al. in 2005. One patient had typical imaging pattern of RE while other four patients had atypical imaging features of RE on PET-MRI.

Rosai-Dorfman disease presenting as cervical extradural lesion: a case report with review of literature.

Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease is a rare, but well documented entity. We report a lady who presented with progressive quadriparesis, with cervical extradural lesion on magnetic resonance imaging. She underwent decompression of the lesion and histological diagnosis of the lesion was Rosai-Dorfman disease. On one-year follow-up, she had complete improvement of the deficits with no further progression of the lesion. The presentation of this disease as an isolated spinal extradural mass lesion is quite rare, with only six cases reported in literature.

Sleep profile and Polysomnography in patients with drug-resistant temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) and the effect of epilepsy surgery on sleep-a prospective cohort study.

OBJECTIVES: We analyzed changes in sleep profile and architecture of patients with drug-resistant TLE-HS using three validated sleep questionnaires- Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), NIMHANS Comprehensive Sleep Disorders, and polysomnography (PSG). We studied the effect of epilepsy surgery in a subset of patients. METHODS: In this prospective observational cohort study, sleep profile of 40 patients with drug-resistant TLE-HS was compared to 40 healthy matched controls. Sleep architecture of 22 patients was studied by overnight PSG and compared to 22 matched controls. Sleep profile was reassessed in 20 patients after a minimum period of three months after epilepsy surgery. RESULTS: The mean PSQI was higher among patients compared to controls(P=0.0004) while mean ESS showed no difference. NCSDQ showed fewer patients feeling refreshed after a night's sleep compared to controls (p=0.006). PSG revealed a higher time in bed (p=0.0001), longer total sleep time (p=0.006) and more time spent in NREM stage 1 (p=0.001) and stage 2 (p=0.005) while spending less time in stage 3 (p=0.039) among TLE patients. Sleep efficiency was worse in patients on ≥3 ASMs compared to those on 2 ASMs (p-0.044). There was no change in mean ESS (p=0.48) or PSQI (p=0.105) after surgery. CONCLUSIONS: Patients with drug-resistant TLE-HS have an altered sleep profile and architecture. Patients on ≥3 ASMs have a lower sleep efficiency. Reassessment at short intervals after epilepsy surgery did not reveal significant changes in sleep profile.

Proteomic identification of haptoglobin α2 as a glioblastoma serum biomarker: implications in cancer cell migration and tumor growth.

Glioblastoma (GBM; grade IV astrocytoma) is the most malignant and common primary brain tumor in adults. Using combination of 2-DE and MALDI-TOF MS, we analyzed 14 GBM and 6 normal control sera and identified haptoglobin α2 chain as an up-regulated serum protein in GBM patients. GBM-specific up-regulation was confirmed by ELISA based quantitation of haptoglobin (Hp) in the serum of 99 GBM patients as against lower grades (49 grade III/AA; 26 grade II/DA) and 26 normal individuals (p = 0.0001). Further validation using RT-qPCR on an independent set (n = 78) of tumor and normal brain (n = 4) samples and immunohistochemcial staining on a subset (n = 42) of above samples showed increasing levels of transcript and protein with tumor grade and were highest in GBM (p = <0.0001 and <0.0001, respectively). Overexpression of Hp either by stable integration of Hp cDNA or exogenous addition of purified Hp to immortalized astrocytes resulted in increased cell migration. RNAi-mediated silencing of Hp in glioma cells decreased cell migration. Further, we demonstrate that both human glioma and mouse melanoma cells overexpressing Hp showed increased tumor growth. Thus, we have identified haptoglobin as a GBM-specific serum marker with a role on glioma tumor growth and migration.