Brief descriptive epidemiology of primary malignant brain tumors from North-East India

The role of NLRP3 and NLRP12 inflammasomes in glioblastoma

Glioblastoma (GBM) is the deadliest malignant brain tumor, with a survival of less than 14 months after diagnosis. The highly invasive nature of GBM makes total surgical resection challenging, leading to tumor recurrence and declined survival. The heterocellular composition of the GBM reprograms its microenvironment, favoring tumor growth, proliferation, and migration. The innate immune cells in the GBM tumor microenvironment, including microglia, astrocytes, and macrophages, express pattern recognition receptors such as NLRs (Nucleotide-binding domain and leucine-rich repeat-containing) that sense pathogen- and damage-associated molecular patterns initiating inflammation. Upon activation, NLRP3 promotes inflammation by NLRP3 inflammasome formation. Auto-proteolytic cleavage and activation of Caspase-1 within the inflammasome leads to caspase-1-mediated cleavage, activation, and conversion of pro-IL-1ß and pro-IL-18 to IL-1ß and IL-18, leading to pyroptosis. In contrast, NLRP12 downregulates inflammatory responses in microglia and macrophages by regulating the NF-κB pathway. NLRP3 and NLRP12 have been implicated in the disease pathophysiology of several cancers with cell-context-dependent, pro- or anti-tumorigenic roles. In this review, we discuss the current literature on the mechanistic roles of NLRP3 and NLRP12 in GBM and the gaps in the scientific literature in the context of GBM pathophysiology with potential for targeted therapeutics.

Genome-Wide Association Study Identifies Multiple Susceptibility Loci for Malignant Neoplasms of the Brain in Taiwan

Primary brain malignancy is a rare tumor with a global incidence of less than 10 per 100,000 people. Hence, there is limited power for identifying risk loci in individual studies, especially for Han Chinese. We performed a genome-wide association study (GWAS) in Taiwan, including 195 cases and 195 controls. We identified five new genes for malignant neoplasms of the brain: EDARADD (rs645507, 1p31.3, p = 7.71 × 10⁻⁵, odds ratio (OR) = 1.893), RBFOX1 (rs8044700, p = 2.35 × 10⁻⁵, OR = 2.36), LMF1 (rs3751667, p = 7.24 × 10⁻⁷, OR = 2.17), DPP6 (rs67433368, p = 8.32 × 10⁻⁵, OR = 3.94), and NDUFB9 (rs7827791, p = 9.73 × 10⁻⁶, OR = 4.42). These data support that genetic susceptibility toward GBM or non-GBM tumors is highly distinct, likely reflecting different etiologies. Combined with signaling analysis, we found that RNA modification may be related to major risk factors in primary malignant neoplasms of the brain.

Gliomas - An experience based on molecular markers

Background

Gliomas account for 45% of all intracranial tumors. Newer technologies have allowed deeper genetic and epigenetic analysis leading to the discovery of IDH (Isocitrate dehydrogenase) mutations and their association with ATRX (alpha-thalassemia/mental retardation syndrome X-linked) and p53, for better diagnosis and prognosis. In this study, we analysed their expression and correlated with various clinicopathological parameters. A follow up to prognosticate gliomas based on the molecular findings is also attempted.

Materials and Method

During last 5 years both retrospective and prospective cases were included in the study. Immunohistochemistry for IDH1, ATRX, and p53 was done and reported based on intensity and percentage of tumor cells expressing the markers.

Results

A total of 53 cases of gliomas were included, excluding primary glioblastomas and ependymomas. The patient's age ranged from 10 to 53 years. The male to female ratio was 1.3:1. IDH1 positivity was seen in 88% of diffuse astrocytoma, 80% of anaplastic astrocytoma, 90% of oligodendroglioma, 60% of anaplastic oligodendroglioma, and 54% of glioblastoma. A significant association was seen between positive IDH1 expression and low-grade gliomas (p = 0.028). A combined analysis of expression of IDH1 and ATRX versus IDH1, ATRX, and p53 with WHO grade showed a statistically significant association. A follow-up of 32 patients was available. Out of 24 IDH1+ (positive) cases, 22 patients had a median survival of 21.5 months (92%). Out of 8 IDH1- (negative) cases, 5 had a median survival of 15.8 months (62%).

Conclusion

Gliomas expressing IDH1 mutation show improved survival of patients. Combined analysis of IDH1, ATRX, and p53 has diagnostic and prognostic significance. For routine cases of gliomas, a combination of IDH1 and ATRX are sufficient; however, the use of p53 is recommended for further prognostication and for possible targeted therapy in the future.

Histopathological Analysis of Brain Tumours- A Seven Year Study from a Tertiary Care Centre in South India

INTRODUCTION

Tumours of central nervous system constitute 1%-2% of tumours in adults. The incidence of brain tumours has been reported to be around 3.9 and 3.0/one lac/year in males and females respectively. A few studies are available from India which show a lower incidence of brain tumours compared to the developed countries. Not much is known about the epidemiology of brain tumours in the population from South India.

AIM

To identify the age groups, gender distribution, topography and different histological types of brain tumours.

MATERIALS AND METHODS

A total of 510 cases of brain tumours were identified over a period of seven years which were included in the present study. We retrieved the slides of these cases and reviewed them. Immunohistochemistry in required cases were done. Age and gender distribution, clinical presentation, site of tumour and histopathologic patterns with grade were noted and the data was analysed with SPSS software version 17.0.

RESULTS

Our analysis showed that most of the brain tumours occur between 40-60 years of age, with a male to female ratio of 0.9:1. Majority of cases involved dura and cerebral lobes except for the occipital lobe, and meningioma and glial tumours were the most common broad histological types. WHO grade IV tumours and metastasis were common in males compared to females.

CONCLUSION

This study revealed the distribution of brain tumours in patients attending our institution. The results obtained were comparable with available worldwide data.