Human leukocyte antigen frequency in human high-grade gliomas: a case-control study in Sicily

Association between brain cancer immunogenetic profile and in silico immunogenicities of 11 viruses

Several viruses including human herpes viruses (HHVs), human polyomavirus JCV, and human papilloma virus (HPV) have been implicated in brain cancer, albeit inconsistently. Since human leukocyte antigen (HLA) is centrally involved in the human immune response to viruses and has been implicated in brain cancer, we evaluated in silico the immunogenicity between 69 Class I HLA alleles with epitopes of proteins of 9 HHVs, JCV, and HPV with respect to a population-based HLA-brain cancer profile. We found that immunogenicity varied widely across HLA alleles with HLA-C alleles exhibiting the highest immunogenicity, and that immunogenicity scores were negatively associated with the population-based HLA-brain cancer profile, particularly for JCV, HHV6A, HHV5, HHV3, HHV8, and HHV7. Consistent with the role of HLA in foreign antigen elimination, the findings suggest that viruses with proteins of high HLA immunogenicity are eliminated more effectively and, consequently, less likely to cause brain cancer; conversely, the absence of highly immunogenic HLA may allow the viral antigens to persist, contributing to cancer.

Positive Association Between the Immunogenetic Human Leukocyte Antigen (HLA) Profiles of Multiple Sclerosis and Brain Cancer

Previous research has documented elevated risk of brain cancer in patients with multiple sclerosis (MS). Separately, human leukocyte antigen (HLA) has been implicated in protection or susceptibility for both conditions. The aim of the current study was to assess a possible role of shared immunogenetic influence on risk of MS and brain cancer. We first identified an immunogenetic profile for each condition based on the covariance between the population frequency of 127 high-resolution HLA alleles and the population prevalence of each condition in 14 Continental Western European countries and then evaluated the correspondence between MS and brain cancer immunogenetic profiles. Also, since each individual carries 12 HLA alleles (2 × 6 genes), we estimated HLA protection and susceptibility for MS and brain cancer at the individual level. We found that the immunogenetic profiles of MS and brain cancer were highly correlated overall (P < .001) and across all 6 HLA genes with the strongest association observed for DRB1, followed by DQB1 and HLA-A. These findings of immunogenetic overlap between MS and brain cancer are discussed in light of the role of HLA in the immune system response to viruses and other foreign antigens.

Minimally Invasive Surgery of Deep-Seated Brain Lesions Using Tubular Retractors and Navigated Transcranial Magnetic Stimulation-Based Diffusion Tensor Imaging Tractography Guidance: The Minefield Paradigm

BACKGROUND

Surgical treatment of deep-seated brain lesions is a major challenge for neurosurgeons. Recently, tubular retractors have been used to help neurosurgeons in achieving the targeting and resection of deep lesions.

OBJECTIVE

To describe a novel surgical approach based on the combination of tubular retractors and preoperative mapping by navigated transcranial magnetic stimulation (nTMS) and nTMS-based diffusion tensor imaging (DTI) tractography for the safe resection of deep-seated lesions.

METHODS

Ten consecutive patients affected by deep-seated brain lesions close to eloquent motor/language/visual pathways underwent preoperative nTMS mapping of motor/language cortical areas and nTMS-based DTI tractography of adjacent eloquent white matter tracts, including optic radiations. The nTMS-based information was used to plan the optimal surgical trajectory and to guide the insertion of tubular retractors within the brain parenchyma without causing injury to the eloquent cortical and subcortical structures. After surgery, all patients underwent a new nTMS-based DTI tractography of fascicles close to the tumor to verify their structural integrity.

RESULTS

Gross total resection was achieved in 8 cases, subtotal resection in 1 case, and a biopsy in 1 case. No new postoperative deficits were observed, except in 1 case where a visual field defect due to injury to the optic radiations occurred. Postoperative nTMS-based DTI tractography showed the integrity of the subcortical fascicles crossed by tubular retractors trajectory in 9 cases.

CONCLUSION

The novel strategy combining tubular retractors with functional nTMS-based preoperative mapping enables a safe microsurgical resection of deep-seated lesions through the preservation of eloquent cortical areas and subcortical fascicles, thus reducing the risk of new permanent deficits.

Forecasting Molecular Features in IDH-Wildtype Gliomas: The State of the Art of Radiomics Applied to Neurosurgery

BACKGROUND

The fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, marks a step forward the future diagnostic approach to these neoplasms. Alongside this, radiomics has experienced rapid evolution over the last several years, allowing us to correlate tumor imaging heterogeneity with a wide range of tumor molecular and subcellular features. Radiomics is a translational field focused on decoding conventional imaging data to extrapolate the molecular and prognostic features of tumors such as gliomas. We herein analyze the state-of-the-art of radiomics applied to glioblastoma, with the goal to estimate its current clinical impact and potential perspectives in relation to well-rounded patient management, including the end-of-life stage.

METHODS

A literature review was performed on the PubMed, MEDLINE and Scopus databases using the following search items: "radiomics and glioma", "radiomics and glioblastoma", "radiomics and glioma and IDH", "radiomics and glioma and TERT promoter", "radiomics and glioma and EGFR", "radiomics and glioma and chromosome".

RESULTS

A total of 719 articles were screened. Further quantitative and qualitative analysis allowed us to finally include 11 papers. This analysis shows that radiomics is rapidly evolving towards a reliable tool.

CONCLUSIONS

Further studies are necessary to adjust radiomics' potential to the newest molecular requirements pointed out by the 2021 WHO classification of CNS tumors. At a glance, its application in the clinical routine could be beneficial to achieve a timely diagnosis, especially for those patients not eligible for surgery and/or adjuvant therapies but still deserving palliative and supportive care.

Review of Intraoperative Adjuncts for Maximal Safe Resection of Gliomas and Its Impact on Outcomes

Maximal safe resection is the mainstay of treatment in the neurosurgical management of gliomas, and preserving functional integrity is linked to favorable outcomes. How these modalities differ in their effectiveness on the extent of resection (EOR), survival, and complications remains unknown. A systematic literature search was performed with the following inclusion criteria: published between 2005 and 2022, involving brain glioma surgery, and including one or a combination of intraoperative modalities: intraoperative magnetic resonance imaging (iMRI), awake/general anesthesia craniotomy mapping (AC/GA), fluorescence-guided imaging, or combined modalities. Of 525 articles, 464 were excluded and 61 articles were included, involving 5221 glioma patients, 7(11.4%) articles used iMRI, 21(36.8%) used cortical mapping, 15(24.5%) used 5-aminolevulinic acid (5-ALA) or fluorescein sodium, and 18(29.5%) used combined modalities. The heterogeneity in reporting the amount of surgical resection prevented further analysis. Progression-free survival/overall survival (PFS/OS) were reported in 18/61(29.5%) articles, while complications and permanent disability were reported in 38/61(62.2%) articles. The reviewed studies demonstrate that intraoperative adjuncts such as iMRI, AC/GA mapping, fluorescence-guided imaging, and a combination of these modalities improve EOR. However, PFS/OS were underreported. Combining multiple intraoperative modalities seems to have the highest effect compared to each adjunct alone.

HLA polymorphisms and risk of glioblastoma in Koreans

Purpose

Immune responses for cancer cells can be altered according to genetic variation of human leukocyte antigen (HLA). Association of HLA polymorphism with risk of various cancer types is well known. However, the association between HLA and glioblastoma (GBM) remains uncertain. We sought to evaluate the association of HLA polymorphism with risk of GBM development in Koreans.

Materials and methods

A case-control study was performed to identify the odds ratios (OR) of HLA class I and II genes for GBM. The control group consisted of 142 healthy Korean volunteers, and the GBM group was 80 patients with newly diagnosed GBM at our institution. HLA class I (-A, -B, and–C) and class II (-DR, -DQ, and–DP) genotyping was performed by high-resolution polymerase chain reaction (PCR)-sequence-based typing (PCR-SBT) methods.

Results

There were significantly decreased frequencies of HLA-A*26:02 (OR 0.22 CI 0.05–0.98), HLA-C*08:01 (OR 0.29 CI 0.10–0.87), and HLA-DRB1*08:03 (OR 0.32 CI 0.11–0.98), while there was significantly increased frequency of HLA-C*04:01 (OR 2.29 CI 1.05–4.97). In analysis of haplotypes, the frequency of DRB1*14:05-DQB1*05:03 was significantly decreased (OR 0.22 CI 0.05–0.98).

Conclusion

This study suggests that genetic variations of HLA may affect GBM development in Koreans. Further investigations with larger sample sizes are needed to delineate any potential role of the HLA polymorphisms in the pathogenesis of GBM development.

Pilocytic Astrocytoma-Derived Cells in Peripheral Blood: A Case Report

Imaging limitations, invasive tissue biopsies and poor information over the course of treatment to evaluate ‘real-time’ tumor dynamics justify the emerging use of liquid biopsies in the field of brain tumors. Circulating tumor cells (CTCs) from high-grade astrocytomas might reach the circulation by crossing the blood–brain barrier. Here, for the first time, CTCs cytology in a case of pylocitic astrocytoma is described. An obstructive hydrocephalous due to a lateral mesencephalic tectum mass occluding the Silvio Aqueduct was diagnosed in a young, 18 years old, male. Considering the location of the tumor and the rapid deterioration of the neurological status, it has been decided to urgency treat the patient with ventriculoperitoneal shunting. Magnetic resonance imaging showed a nodular shaped lesion localized within the left lateral mesencephalic tectum. Stereotactic biopsy was not approachable due significant risk of neurological consequences. The diagnosis was performed by blood sampling, a non-invasive procedure for the patient, in order to provide tumor information. Cytopathological features on detected circulating atypical GFAP positive cells led to pilocytic diagnosis confirmed by the patient’s 68 months outcome.

Expression of PLAG1, HMGA1 and HMGA2 in minor salivary glands tumours

Background

Diagnosis of minor salivary gland (MSG) tumours is often difficult, due to the scarce tissue obtained from bioptic excision and complex histopathological differential diagnosis. In our study we performed an immunohistochemical analysis of PLAG1, HMGA1 and HMGA2 on a series of MSG tumours, in order to develop a new helpful diagnostic panel.

Methods

A retrospective series of 17 surgical specimens of MSG tumours were analysed for the expression of PLAG1, HMGA1 and HMGA2. Three control cases were enrolled and analysed. An intensity and percentage-based approach was performed, creating a combined score panel.

Results

PLAG1 facilitate the diagnosis of benign tumours, discriminating it from malignant histotypes, with a defined cut-off value. Similarly, HMGA1 is significantly higher in benign histotypes than in malignant ones. HMGA2 in our series, did not reveal any association in identifying benign from malignant histotypes.

Conclusions

In this study we assessed the diagnostic role of PLAG1, HMGA1 and HMGA2 immunohistochemical analysis. The score panel facilitate histopathological diagnosis of these rare tumours, helping to distinguish benign tumours from malignant ones and ameliorating the differential diagnosis of specific histotypes.

A rare diagnosis of an extraventricular neurocytoma

Background:

Extraventricular neurocytoma (EVN) is an extremely rare neoplasm of the central nervous system. As reported, it arises in a variety of locations, but mainly within the cerebral hemispheres. Despite its histological similarity with central neurocytoma (CN), EVN occurs outside the ventricular system and, in 2007, was recognized by the World Health Organization as a separate entity.

Case Description:

A 39-year-old man, with a ventriculoperitoneal shunt inserted for communicating hydrocephalus, was admitted at our Unit of Neurosurgery with a 1-month history of gait disturbance, postural instability, speech disorders, and occasional incontinence. Computed tomography scan and magnetic resonance imaging showed a mixed-density neoplasm in the left frontotemporal area, with anterior cerebral falx shift, and perilesional edema. The patient underwent surgical procedure; microsurgical excision of the lesion was performed through left pterional approach. Histopathological and immunohistochemical examination revealed monomorphic round cells of the neuronal lineage, with a percentage of Ki-67 positive nuclei <5% and no evidence of mitosis or necrotic areas. According to radiologic features, this pattern was compatible with the diagnosis of EVN. Patient had a favorable recovery and he is still in follow-up.

Conclusion:

Because of their rarity, clinical, radiologic, and histopathological characteristics of EVNs are not yet well defined, as well as the optimal therapeutic management. Whereas EVNs are rarely described in literature, we aimed to share and discuss our experience along with a review of the published literature.

Navigated Transcranial Magnetic Stimulation Motor Mapping Usefulness in the Surgical Management of Patients Affected by Brain Tumors in Eloquent Areas: A Systematic Review and Meta-Analysis

Background: The surgical strategy for brain glioma has changed, shifting from tumor debulking to a more careful tumor dissection with the aim of a gross-total resection, extended beyond the contrast-enhancement MRI, including the hyperintensity on FLAIR MR images and defined as supratotal resection. It is possible to pursue this goal thanks to the refinement of several technological tools for pre and intraoperative planning including intraoperative neurophysiological monitoring (IONM), cortico-subcortical mapping, functional MRI (fMRI), navigated transcranial magnetic stimulation (nTMS), intraoperative CT or MRI (iCT, iMR), and intraoperative contrast-enhanced ultrasound. This systematic review provides an overview of the state of the art techniques in the application of nTMS and nTMS-based DTI-FT during brain tumor surgery.

Materials and Methods: A systematic literature review was performed according to the PRISMA statement. The authors searched the PubMed and Scopus databases until July 2020 for published articles with the following Mesh terms: (Brain surgery OR surgery OR craniotomy) AND (brain mapping OR functional planning) AND (TMS OR transcranial magnetic stimulation OR rTMS OR repetitive transcranial stimulation). We only included studies regarding motor mapping in craniotomy for brain tumors, which reported data about CTS sparing.

Results: A total of 335 published studies were identified through the PubMed and Scopus databases. After a detailed examination of these studies, 325 were excluded from our review because of a lack of data object in this search. TMS reported an accuracy range of 0.4–14.8 mm between the APB hotspot (n1/4 8) in nTMS and DES from the DES spot; nTMS influenced the surgical indications in 34.3–68.5%.

Conclusion: We found that nTMS can be defined as a safe and non-invasive technique and in association with DES, fMRI, and IONM, improves brain mapping and the extent of resection favoring a better postoperative outcome.

Brain Mapping-Aided SupraTotal Resection (SpTR) of Brain Tumors: The Role of Brain Connectivity

Brain gliomas require a deep knowledge of their effects on brain connectivity. Understanding the complex relationship between tumor and functional brain is the preliminary and fundamental step for the subsequent surgery. The extent of resection (EOR) is an independent variable of surgical effectiveness and it correlates with the overall survival. Until now, great efforts have been made to achieve gross total resection (GTR) as the standard of care of brain tumor patients. However, high and low-grade gliomas have an infiltrative behavior and peritumoral white matter is often infiltrated by tumoral cells. According to these evidences, many efforts have been made to push the boundary of the resection beyond the contrast-enhanced lesion core on T1w MRI, in the so called supratotal resection (SpTR). SpTR is aimed to maximize the extent of resection and thus the overall survival. SpTR of primary brain tumors is a feasible technique and its safety is improved by intraoperative neuromonitoring and advanced neuroimaging. Only transient cognitive impairments have been reported in SpTR patients compared to GTR patients. Moreover, SpTR is related to a longer overall and progression-free survival along with preserving neuro-cognitive functions and quality of life.

New Hope in Brain Glioma Surgery: The Role of Intraoperative Ultrasound. A Review

Maximal safe resection represents the gold standard for surgery of malignant brain tumors. As regards gross-total resection, accurate localization and precise delineation of the tumor margins are required. Intraoperative diagnostic imaging (Intra-Operative Magnetic Resonance-IOMR, Intra-Operative Computed Tomography-IOCT, Intra-Operative Ultrasound-IOUS) and dyes (fluorescence) have become relevant in brain tumor surgery, allowing for a more radical and safer tumor resection. IOUS guidance for brain tumor surgery is accurate in distinguishing tumor from normal parenchyma, and it allows a real-time intraoperative visualization. We aim to evaluate the role of IOUS in gliomas surgery and to outline specific strategies to maximize its efficacy. We performed a literature research through the Pubmed database by selecting each article which was focused on the use of IOUS in brain tumor surgery, and in particular in glioma surgery, published in the last 15 years (from 2003 to 2018). We selected 39 papers concerning the use of IOUS in brain tumor surgery, including gliomas. IOUS exerts a notable attraction due to its low cost, minimal interruption of the operational flow, and lack of radiation exposure. Our literature review shows that increasing the use of ultrasound in brain tumors allows more radical resections, thus giving rise to increases in survival.

Brain Mapping as Helpful Tool in Brain Glioma Surgical Treatment-Toward the "Perfect Surgery"?

Gliomas are the most common primary malignant brain tumours in adults, representing nearly 80%, with poor prognosis in their high-grade forms. Several variables positively affect the prognosis of patients with high-grade glioma: young age, tumour location, radiological features, recurrence, and the opportunity to perform post-operative adjuvant therapy. Low-grade gliomas are slow-growing brain neoplasms of adolescence and young-adulthood, preferentially involving functional areas, particularly the eloquent ones. It has been demonstrated that early surgery and higher extent rate ensure overall longer survival time regardless of tumour grading, but nowadays, functional preservation that is as complete as possible is imperative. To achieve the best surgical results, along with the best functional results, intraoperative mapping and monitoring of brain functions, as well as different anaesthesiology protocols for awake surgery are nowadays being widely adopted. We report on our experience at our institution with 28 patients affected by malignant brain tumours who underwent brain mapping-aided surgical resection of neoplasm: 20 patients underwent awake surgical resection and 8 patients underwent asleep surgical resection. An analysis of the results and a review of the literature has been performed.

End-of-Life Care in High-Grade Glioma Patients. The Palliative and Supportive Perspective

High-grade gliomas (HGGs) are the most frequently diagnosed primary brain tumors. Even though it has been demonstrated that combined surgical therapy, chemotherapy, and radiotherapy improve survival, HGGs still harbor a very poor prognosis and limited overall survival. Differently from other types of primary neoplasm, HGG manifests also as a neurological disease. According to this, palliative care of HGG patients represents a peculiar challenge for healthcare providers and caregivers since it has to be directed to both general and neurological cancer symptoms. In this way, the end-of-life (EOL) phase of HGG patients appears to be like a journey through medical issues, progressive neurological deterioration, and psychological, social, and affective concerns. EOL is intended as the time prior to death when symptoms increase and antitumoral therapy is no longer effective. In this phase, palliative care is intended as an integrated support aimed to reduce the symptoms burden and improve the Quality Of Life (QOL). Palliative care is represented by medical, physical, psychological, spiritual, and social interventions which are primarily aimed to sustain patients&rsquo; functions during the disease time, while maintaining an acceptable quality of life and ensuring a dignified death. Since HGGs represent also a family concern, due to the profound emotional and relational issues that the progression of the disease poses, palliative care may also relieve the distress of the caregivers and increase the satisfaction of patients&rsquo; relatives. We present the results of a literature review addressed to enlighten and classify the best medical, psychological, rehabilitative, and social interventions that are addressed both to patients and to their caregivers, which are currently adopted as palliative care during the EOL phase of HGG patients in order to orientate the best medical practice in HGG management.

With a Little Help from My Friends: The Role of Intraoperative Fluorescent Dyes in the Surgical Management of High-Grade Gliomas

High-grade gliomas (HGGs) are the most frequent primary malignant brain tumors in adults, which lead to death within two years of diagnosis. Maximal safe resection of malignant gliomas as the first step of multimodal therapy is an accepted goal in malignant glioma surgery. Gross total resection has an important role in improving overall survival (OS) and progression-free survival (PFS), but identification of tumor borders is particularly difficult in HGGS. For this reason, imaging adjuncts, such as 5-aminolevulinic acid (5-ALA) or fluorescein sodium (FS) have been proposed as superior strategies for better defining the limits of surgical resection for HGG. 5-aminolevulinic acid (5-ALA) is implicated as precursor in the synthetic pathway of heme group. Protoporphyrin IX (PpIX) is an intermediate compound of heme metabolism, which produces fluorescence when excited by appropriate light wavelength. Malignant glioma cells have the capacity to selectively synthesize or accumulate 5-ALA-derived porphyrins after exogenous administration of 5-ALA. Fluorescein sodium (FS), on the other hand, is a fluorescent substance that is not specific to tumor cells but actually it is a marker for compromised blood-brain barrier (BBB) areas. Its effectiveness is confirmed by multicenter phase-II trial (FLUOGLIO) but lack of randomized phase III trial data. We conducted an analytic review of the literature with the objective of identifying the usefulness of 5-ALA and FS in HGG surgery in adult patients.

Decreased human leukocyte antigen A*02:01 frequency is associated with risk of glioma and existence of human cytomegalovirus: a case-control study in Northern China

BACKGROUND

Human leukocyte antigens (HLAs) play an important role in host defense against viral infection and tumorigenesis. Human cytomegalovirus (HCMV) has been linked to glioma development. This study investigated the relationship between HLA distribution, presence of HCMV, and glioma development in a Han Chinese population.

METHODS

The study population included 150 glioma patients and 150 tumor-free brain injury control subjects (control-A) matched according to geography, ethnicity, age, and gender. HLA allele frequency was compared between the two groups using peripheral blood samples by PCR sequence-based typing. These data were also compared with HLA frequencies obtained from a Northern Chinese Han population database (control-B). HCMV DNA was detected in the peripheral blood of glioma patients and control group-A by nested PCR. The expression of HCMV proteins IE1-72 and pp65 in tumor tissues was evaluated by immunohistochemistry.

RESULTS

The frequency of HLA-A*02:01 was decreased in glioma patients as compared to control group-A and -B (P < 0.001 and P = 0.001, respectively). The age/sex-adjusted odds ratio for HLA-A*02:01 positivity vs. negativity was 0.392 (95% confidence interval 0.225-0.683). HCMV was more frequently detected in the peripheral blood and tumor tissue of HLA-A*02:01-negative glioma patients. HLA-A*02:01 and HCMV were not associated with overall survival.

CONCLUSION

There is a correlation between decreased HLA-A*0201 allele frequency and glioma susceptibility.

A thoracic vertebral localization of a metastasized cutaneous Merkel cell carcinoma: Case report and review of literature

Background:

Merkel cell carcinoma (MCC) is a rare neuroendocrine skin tumor, which may be related to sun exposure. It can metastasize to lungs, liver and bone, leading to severe morbidity and mortality. Vertebral metastases from MCC are rare. The authors report the tenth case in the literature, a 59-year-old patient with MCC, which was primarily localized in the scalp, and later provoked distant metastasis to the thoracic spinal column.

Case Description:

A 59-year-old woman was admitted at our Unit of Neurosurgery with a 4-month history of progressive and severe dorsal back pain, without neurological signs. The patient had been surgically treated for a recidivated MCC in the occipital region in 2007, 2011, and 2013. (In 2013, the surgical treatment also included lateral cervical lymph node dissection). Chemotherapy and radiotherapy had come after the treatments. Magnetic resonance imaging (MRI) of the dorsal spine showed metastatic vertebral involvement with cord impingement of the T7-T8 levels. A total body CT scan revealed lungs and liver metastases, besides vertebral district. After a multidisciplinary consult a palliative surgery was decided and a posterior dorsal approach was employed: Radiofrequency (RF) thermoablation was followed by the injection of cement of T7 and T8 and transpedicle fixation T5-T9. The postoperative course was uneventful and followed by a further adjuvant therapy

Conclusion:

Spinal metastases from MCC are described in literature only exceptionally. The clinical course is presented, along with a review of literature.

Non-additive and epistatic effects of HLA polymorphisms contributing to risk of adult glioma

Although genome-wide association studies have identified several susceptibility loci for adult glioma, little is known regarding the potential contribution of genetic variation in the human leukocyte antigen (HLA) region to glioma risk. HLA associations have been reported for various malignancies, with many studies investigating selected candidate HLA polymorphisms. However, no systematic analysis has been conducted in glioma patients, and no investigation into potential non-additive effects has been described. We conducted comprehensive genetic analyses of HLA variants among 1746 adult glioma patients and 2312 controls of European-ancestry from the GliomaScan Consortium. Genotype data were generated with the Illumina 660-Quad array, and we imputed HLA alleles using a reference panel of 5225 individuals in the Type 1 Diabetes Genetics Consortium who underwent high-resolution HLA typing via next-generation sequencing. Case-control comparisons were adjusted for population stratification using ancestry-informative principal components. Because alleles in different loci across the HLA region are linked, we created multigene haplotypes consisting of the genes DRB1, DQA1, and DQB1. Although none of the haplotypes were associated with glioma in additive models, inclusion of a dominance term significantly improved the model for multigene haplotype HLA-DRB1*1501-DQA1*0102-DQB1*0602 (P = 0.002). Heterozygous carriers of the haplotype had an increased risk of glioma [odds ratio (OR) 1.23; 95% confidence interval (CI) 1.01-1.49], while homozygous carriers were at decreased risk compared with non-carriers (OR 0.64; 95% CI 0.40-1.01). Our results suggest that the DRB1*1501-DQA1*0102-DQB1*0602 haplotype may contribute to the risk of glioma in a non-additive manner, with the positive dominance effect partly explained by an epistatic interaction with HLA-DRB1*0401-DQA1*0301-DQB1*0301.

Fluorescein for resection of high-grade gliomas: A safety study control in a single center and review of the literature

BACKGROUND

The importance of a complete resection of high-grade gliomas (HGGs) has been highlighted in scientific literature, in order to limit tumor recurrence and above all to improve disease-free survival rates. Several fluorescent biomarkers have been tested to improve intraoperative identification of residual tumor; 5-aminolevulinic acid (5-ALA) and fluorescein sodium (FS) are now starting to play a central role in glioma surgery. We performed a retrospective analysis on 47 patients operated for HGGs. Here we report our preliminary data.

METHODS

Data of 47 consecutive patients with HGG have been collected in our study (25 males, 22 females; mean age: 60.3 years, range: 27-86 years). Fluorescein (5 mg/kg of body weight) was injected intravenously right after the induction of general anesthesia. A YELLOW 560 filter was used on an OPMI Pentero 900 microscope (Carl Zeiss Meditec, Oberkochen, Germany) to complete a microsurgical tumor removal. Glioma resection and quality of life were evaluated preoperative and postoperatively.

RESULTS

Gross total resection (GTR) was achieved in 53.2% (n = 25) of patients. A subtotal resection (STR) (>95%) was achieved in 29.8% (n = 14), while a partial resection (PR) (<95%) was obtained in 17% (n = 8) of patients. Overall, in 83% (n = 39) of patients who underwent fluorescence-guided surgery the resection rate achieved was >95%. No adverse effects correlated to fluorescein have been recorded.

CONCLUSION

Fluorescein seems to be safe and effective in the resection of HGGs, allowing a high rate of gross total removal of contrast enhanced areas.

Analysis of gene expression profiles associated with glioma progression

The present study aimed to investigate changes at the transcript level that are associated with spontaneous astrocytoma progression, and further, to discover novel targets for glioma diagnosis and therapy. GSE4290 microarray data downloaded from Gene Expression Omnibus were used to identify the differentially expressed genes (DGEs) by significant analysis of microarray (SAM). The Short Time Series Expression Miner (STEM) method was then applied to class these DEGs based on their degrees of differentiation in the process of tumor progression. Finally, EnrichNet was used to perform the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis based on a protein-protein interaction (PPI) network. A total of 4,506 DEGs were detected, and the number of DEGs was the highest in grade IV cells (2,580 DEGs). These DEGs were classified into nine clusters by the STEM method. In total, 11 KEGG pathways with XD-scores larger than the threshold (0.96) were obtained. The DEGs enriched in pathways 1 (extracellular matrix-receptor interaction), 3 (phagosome) and 6 (type I diabetes mellitus) mainly belonged to cluster 5. Pathway 2 (long-term potentiation), 4 (Vibrio cholerae infection) and 5 (epithelial cell signaling in Helicobacter pylori infection) was involved with DEGs that belonged to different clusters. Significant changes in gene expression occurred during glioma progression. Pathways 1, 3 and 6 may be important for the deterioration of glioma into glioblastoma, and pathways 2, 4 and 5 may have a role at each stage during glioma progression. The associated DEGs, including SV2, NMDAR and mGluRs, may be suitable as biomarkers or therapeutic targets for gliomas.

Case-control studies in neurosurgery

OBJECT

Observational studies, such as cohort and case-control studies, are valuable instruments in evidence-based medicine. Case-control studies, in particular, are becoming increasingly popular in the neurosurgical literature due to their low cost and relative ease of execution; however, no one has yet systematically assessed these types of studies for quality in methodology and reporting.

METHODS

The authors performed a literature search using PubMed/MEDLINE to identify all studies that explicitly identified themselves as "case-control" and were published in the JNS Publishing Group journals (Journal of Neurosurgery, Journal of Neurosurgery: Pediatrics, Journal of Neurosurgery: Spine, and Neurosurgical Focus) or Neurosurgery. Each paper was evaluated for 22 descriptive variables and then categorized as having either met or missed the basic definition of a case-control study. All studies that evaluated risk factors for a well-defined outcome were considered true case-control studies. The authors sought to identify key features or phrases that were or were not predictive of a true case-control study. Those papers that satisfied the definition were further evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist.

RESULTS

The search detected 67 papers that met the inclusion criteria, of which 32 (48%) represented true case-control studies. The frequency of true case-control studies has not changed with time. Use of odds ratios (ORs) and logistic regression (LR) analysis were strong positive predictors of true case-control studies (for odds ratios, OR 15.33 and 95% CI 4.52-51.97; for logistic regression analysis, OR 8.77 and 95% CI 2.69-28.56). Conversely, negative predictors included focus on a procedure/intervention (OR 0.35, 95% CI 0.13-0.998) and use of the word "outcome" in the Results section (OR 0.23, 95% CI 0.082-0.65). After exclusion of nested case-control studies, the negative correlation between focus on a procedure/intervention and true case-control studies was strengthened (OR 0.053, 95% CI 0.0064-0.44). There was a trend toward a negative association between the use of survival analysis or Kaplan-Meier curves and true case-control studies (OR 0.13, 95% CI 0.015-1.12). True case-control studies were no more likely than their counterparts to use a potential study design "expert" (OR 1.50, 95% CI 0.57-3.95). The overall average STROBE score was 72% (range 50-86%). Examples of reporting deficiencies were reporting of bias (28%), missing data (55%), and funding (44%).

CONCLUSIONS

The results of this analysis show that the majority of studies in the neurosurgical literature that identify themselves as "case-control" studies are, in fact, labeled incorrectly. Positive and negative predictors were identified. The authors provide several recommendations that may reverse the incorrect and inappropriate use of the term "case-control" and improve the quality of design and reporting of true case-control studies in neurosurgery.

Glioma Indian scenario: Is there a human leucocyte antigen association?

Background:

The central nervous system tumors are a rare neoplasm with little knowledge with Human Leukocyte Antigen (HLA) involvement. Primary brain tumors are cancers that originate in brain classified according to their appearance under a microscope as low grade (grade I and II) with diffuse astrocytomas, pliocytic astrocytomas, oligodendrogliomas, gangliogliomas, and mixed gliomas as common subtypes and high grade (grade III and IV).

Materials and Methods:

HLA associations in common glioma are reported from other parts of the world. The normal cancer treatment is surgery, followed by radiotherapy, and chemotherapy; nowadays immunotherapy is advised. HLA distribution in a Glioma patient was done based on serology and molecular techniques. The immune response gene studies have implicated the HLA allele association in most of the common diseases from India. Considerable variations are noted in HLA association with cancers; hence, we have summarized the HLA involvement in Glioma with respect to the literature.

Results:

HLA A*030101, A*310102, B*350101, B*4406, Cw*040101, Cw*070101, DRB1*070101, and DRB1*1001.

Conclusion:

Ethnic diversity and HLA polymorphism precipitate differential immune response genes involved in variable disease manifestations. Therefore, caste-specific HLA allelic specificity needs to be identified, which may help in early identification of the associated HLA allele and establishing clinical practices among glioma patients.

Selected human leukocyte antigen class II polymorphisms and risk of adult glioma

Few studies have examined the relationship between human leukocyte antigen (HLA) polymorphisms and adult glioma, particularly at class II loci. We evaluated the association between selected HLA class II polymorphisms and adult glioma in a large, hospital-based case-control study, using unconditional logistic regression. DQB1 06 (OR=1.67, 95% CI=1.17-2.39) and DRB1 13 (OR=1.69, 95% CI=1.08-2.64) alleles were associated with an increased risk of glioma, while the DQB1 05 allele showed an inverse association (OR=0.63, 95% CI=0.43-0.93). These results, which were of borderline significance once controlled for the false discovery rate, suggest a potential role for the DQB1 06, DQB1 05, and DRB1 13 alleles in glioma susceptibility.