Molecular subtyping of medulloblastoma on the basis of immunohistochemistry at Chughtai Institute of Pathology, a single-center experience.

Abstract

Objective: To determine the frequency of medulloblastoma subtypes using IHC markers (β-catenin, YAP1, TP53). Study Design: Cross-sectional study. Setting: The Chughtai Institute of Pathology. Period: June 2024 to June 2025. Methods: Twenty-one new diagnoses of medulloblastoma were included and H&E staining for histological variants was processed. Then immune staining using β-catenin, YAP1, and TP53 was performed. The staining results were used to classify medulloblastoma into its subtypes. Chi-square testing and descriptive statistics were used to conduct the statistical analysis. Results: Classic variant was found to be the most common histological type of medulloblastoma. The most frequently detected subtype of medulloblastoma was the Group 3/4 (76.2%), followed by the SHH subtype (23.8%). No WNT subtype was detected. The identification of WNT tumors by nuclear β-catenin negativity and the identification of desmoplastic/nodular histology by the expression of YAP1 were significantly associated (p=0.021). Conclusion: IHC-based molecular subtyping is a cost-effective and reliable method for classifying medulloblastomas in resource limited situations. This can help to individualize therapies for medulloblastomas patients.