Retrospective analysis and comparison of immunohistochemical features of surgically treated primary-metastatic brain tumours.

Introduction: Malignant tumours diagnosed in the central nervous system are among the leading causes of death from cancer. Central nervous system tumours are the 10th most frequent cause of mortality due to cancer. Immunohistochemistry has become an important tool in the diagnosis of brain tumours. Brain tissue and meninges tumours comprise a heterogeneous group with diverse biological behaviour, treatment management, and different prognoses. Although conventional haematoxylin-eosin staining is crucial for diagnosis, diagnostic neuropathology has benefited from the inclusion of immunohistochemistry and recent advances in the field over the past 20 years. GFAP, S100, IDH, OLIG 2, EMA, ATRX, P53 and Ki67 are the most frequently used immunohistochemical markers globally, which we also highlighted in our study.

Material and methods: Ninety-seven cases including primary-metastatic intracranial tumours, operated on in the Neurosurgery Clinic and diagnosed in the Medical Pathology Laboratory between 2018 and 2023 years, were examined retrospectively from the archive. Haematoxylin-eosin slides were re-evaluated under the light microscope by 2 double-blind pathologists and immunohistochemical features and characteristics of tumours were examined. Data were analysed using the program SPSS 22. Differences were accepted as statistically significant at p < 0.05.

Results: According to the analysis of results, 46 (47.4%) of the 97 included patients were female and 51 (52.6%) were male. The most common tumour types were meningioma with 31 (32%) and high-grade neuroglial tumours with 31 (32%). GFAP, OLIG2, ATRX, and P53 values were found to be significantly higher in high-grade neuroglial tumours. While S 100 and EMA values were especially high in meningiomas, a positive correlation was found with IDH value in low-grade neuroglial tumours. The study showed that the median Ki67 value was significantly higher in high-grade neuroglial tumours and metastatic tumours.

Conclusions: Intracranial tumours cause significant morbidity and mortality in patients. Diagnostic, prognostic and predictive biomarkers evaluated in patient biopsy specimens and/or body fluids are important in neuropathological oncology. By regularly updating our biomarkers and following new treatment approaches, we can improve survival with rapid diagnosis and appropriate treatment in central nervous system tumours after surgery.