Role of Immunohistochemistry in the Diagnosis and Clinicopathological Stratification of Gliomas.

Introduction Gliomas are common primary brain tumors. Immunohistochemical components, such as isocitrate dehydrogenase (IDH) mutations, GFAP (glial fibrillary acidic protein), ATRX (alpha-thalassemia/mental retardation, X-linked), and Ki-67, play a pivotal role in glioma diagnostic classification and risk stratification in prior literature. This study aimed to evaluate the association of IDH1 (R132H) IHC as a surrogate marker within the World Health Organization (WHO) integrated framework and to correlate the expression of IDH1 (R132H) with clinicopathological parameters in gliomas. Methods A hospital-based cross-sectional study was conducted on 30 histologically confirmed glioma cases, with an age range from 1 to 70 years. Clinicopathological parameters such as age of the patient, gender, tumor location, histological type, and World Health Organization tumor grade were recorded. Immunohistochemistry for IDH1 (R132H), Ki-67, GFAP, and ATRX was performed. Associations were assessed using Fisher's exact test (2×2 tables) and Fisher-Freeman-Halton exact test (r×c tables), with p < 0.05 considered significant. Results IDH1 (R132H) immunopositivity was seen in 19 cases (63.3%). ATRX retention was observed in 63.3% of cases, GFAP positivity in 93.3%, and a high Ki-67 index in 50% of cases. IDH1 (R132H) IHC status showed a statistically significant association with age, histological type, and WHO grade. No statistically significant association was observed with gender, ATRX, GFAP, or Ki-67 expression. Conclusion IDH1 (R132H) immunohistochemical expression showed a significant association with established clinicopathological indicators, including patient age, histological type, and WHO tumor grade. In this hospital-based cross-sectional study, IDH1 (R132H) IHC-negative status was more frequently observed in higher-grade tumors. These findings support the use of immunohistochemistry as an accessible adjunct in glioma diagnosis and clinicopathological stratification; outcome-based prognostic significance requires longitudinal follow-up.