Comparison of Molecular Markers and Classical Histopathological Diagnostic Methods in Grade II and III Glial Tumors and Their Prognostic Outcomes.

Aim: To demonstrate the changes in Grade II and III glial tumors after WHO 2016 Brain Tumors Classification.

Material And Methods: The previous diagnoses and postoperative treatment of the 83 patients were recorded. We used real-time PCR (mutation assay) for the analysis of IDH1 and IDH2, while we used FISH test to determine 1p/19q codeletion. The integrated diagnosis was compared with classical histopathological diagnoses.

Results: We studied 13 oligodendendrogliomas, 41 astrocytomas and 29 oligoastrocytomas patients with classical histopathological diagnosis group. IDH mutation was detected in 51 of the patients after genetic analysis, whereas 1p/19q codeletion was detected in 20 patients. We found that grade II IDH-mut astrocytoma patients had significantly better survival outcomes compared to grade III IDH-mut astrocytoma patients.

Conclusion: Grade II and III gliomas are separated into more homogeneous diagnostic groups for survival after molecular marker analyses. Compared to histopathological diagnosis, the WHO 2016 glioma classification with molecular markers provides new perspectives in patient prognosis and treatment. However, due to the costs of using molecular markers, the extent to which it can be used remains questionable.