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Background Pilocytic astrocytomas (PAs) are the primary tumors most frequently found in children and adolescents, accounting for 5.4% of all gliomas. The overall prognosis of PAs is good, yet a substantial no of cases have a poor outcome, with recurrence, and ultimately death. The KIAA1549-BRAF fusion is a useful putative diagnostic marker for PAs and BRAF also is an important therapeutic marker. Aim and Objectives To study the frequency of KIAA1549-BRAF fusion (16-9, 15-9 and 16-11) in different locations of PAs using qRT-PCR technique in FFPE samples. Methodology Three different exon rearrangements of KIAA1549-BRAF (16-9, 15-9 and 16-11) fusions were assessed in 50 cases of PAs by using qRT-PCR (gold standard). FISH assay was also performed in all the cases. Results Out of 50 PAs, 32 were localised in midline structures such as the cerebellum, optic pathway, hypothalamus, and brain stem while 18 in non-midline regions like the cerebral hemispheres. Majority of the cases (35/50); 70% were positive for KIAA1549-BRAF fusion by RT-PCR. Of these, (16/35); 45.7% harboured 15-9 fusion, (15/35); 42.8% harboured 16-9 fusion, and only (4/35); 11.4% had 16-11 fusion. Only (24/30); 48% KIAA1549-BRAF showed fusion by FISH assay. There was 54.2% concordance between FISH and RT-PCR results. KIAA1549-BRAF fusion was observed in 78% of midline and 55.5% of non-midline cases. The frequency of KIAA1549-BRAF fusion decreased with increasing age, 77% in the age group <20, 54% in the age group 20-40 and 30% in the age group >40. Conclusion 15-9 and 16-9 KIAA1549-BRAF were the most frequently occurring fusions dominantly seen in the midline. The presence of fusion is inversely proportional to the age of patients. qRT-PCR is the gold standard technique and FISH assay has moderate concordance with qRT-PCR platform.

Challenges in obtaining tissue specimens and tumor heterogeneity are major limitations for accurate diagnosis, molecular characterization, risk stratification, and development of biomarker-driven therapies in central nervous system (CNS) tumors. The potential of assessment of CNS tumors through analysis of corporeal fluids (liquid biopsy) is being explored to document tumor-related genetic/epigenetic alterations and protein expression to identify prognostic and therapeutic biomarkers. The quantity of circulating tumor DNA isolated also appears to be directly associated with tumor progression and response to treatment. In this review, we provide synopsis of the recent studies which have provided crucial insights into analyzing circulating tumor cells, cell-free nucleic acids, and extracellular vesicles for directing long-term disease control. We have also highlighted the stumbling blocks and gaps in technology that need to be overcome to translate research findings into a tool in the clinical setting.

IDH wild-type (wt) grade 2/3 astrocytomas are a heterogenous group of tumors with disparate clinical and molecular profiles. cIMPACT-NOW recommendations incorporated in the new 2021 World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors urge minimal molecular criteria to identify a subset that has an aggressive clinical course similar to IDH-wt glioblastomas (GBMs). This paper describes the use of a panel of molecular markers to reclassify IDH-wt grade 2/3 diffuse astrocytic gliomas (DAGs) and study median overall survival concerning for to IDH-wt GBMs in the Indian cohort. IDH-wt astrocytic gliomas (grades 2, 3, and 4) confirmed by IDHR132H immunohistochemistry and IDH1/2 gene sequencing, 1p/19q non-codeleted with no H3F3A mutations were included. TERT promoter mutation by Sanger sequencing, epidermal growth factor receptor amplification, and whole chromosome 7 gain and chromosome 10 loss by fluorescence in situ hybridization was assessed and findings correlated with clinical and demographic profiles. The molecular profile of 53 IDH-wt DAGs (grade 2: 31, grade 3: 22) was analyzed. Eleven cases (grade 2: 8, grade 3: 3) (20.75%) were reclassified as IDH-wt GBMs, WHO grade 4 (TERT promoter mutation in 17%, epidermal growth factor receptor amplification in 5.5%, and whole chromosome 7 gain and chromosome 10 loss in 2%). Molecular GBMs were predominantly frontal (54.5%) with a mean age of 36 years and median overall survival equivalent to IDH-wt GBMs (18 vs. 19 mo; P = 0.235). Among grade 2/3 DAGs not harboring these alterations, significantly better survival was observed for grade 2 versus grade 3 DAGs (25 vs. 16 mo; P = 0.002). Through the incorporation of a panel of molecular markers, a subset of IDH-wt grade 2 DAGs can be stratified into molecular grade 4 tumors with prognostic and therapeutic implications. However, IDH-wt grade 3 DAGs behave like GBMs irrespective of molecular profile.

Purpose: Pilocytic astrocytoma (PA) is a central nervous system (CNS) World Health Organization (WHO) grade 1 glial tumor that is highly prevalent in children and young adults. The main aim of the study was to assess the frequency, clinicopathological features and treatment of PAs along with their immunohistochemical and molecular analyses. Methods: Approximately, 144 glial tumors were diagnosed in patients from 3 to 75 yrs of age from January 2015 to March 2022. The tumors were classified according to 2021 CNS WHO classification. Nine pediatric PA patients were identified and their clinical data analyzed. Immunohistochemistry (IHC), fluorescence in-situ hybridization (FISH) and molecular analysis using the real time polymerase chain reaction (RT-PCR) were performed for the PAs. Standard deviations were calculated using the Microsoft excel for statistical validations. Results: The mean age of the glioma patients was 41.7 yrs ± 18.2 with a male/female ratio of 1.3:1. The most common form of glial tumor was found to be astrocytoma CNS WHO grade 2 (31.9 %). Other frequently occurring tumors were astrocytoma CNS WHO grade 3 (29.2 %), astrocytoma CNS WHO grade 4 (13.9 %), diffuse astrocytoma CNS WHO grade 2 (7.4 %), PA CNS WHO grade 1 (6.9 %), and oligodendroglioma CNS WHO grade 3 (4.2 %). The pediatric PA cohort had a mean age of 9.2 yrs ± 4.9 with a male/female ratio of 2:1. Glial fibrillary acidic protein (GFAP) positive immunostaining and retention of transcriptional regulator ATRX expression was seen in all the tested PAs. None of the PAs showed isocitrate dehydrogenase (IDH1), MIB1, and tumor protein p53 expression. The KIAA1459-BRAF fusion was detected in four PAs. Surgical intervention with total or radical tumor excision was performed for the PA patients. Most PA patients exhibited improved condition post-surgery. Conclusion: With the advent of healthcare and newer diagnostic facilities there is increased incidence of glial tumors in developing countries. Combination of histological, immunohistochemical, and molecular analysis is very important for the diagnosis, accurate treatment, and prognosis of PA patients.