Статус та прогностичне значення IDH1 у дорослих пацієнтів із дифузними гліомами 4-го ступеня

Background and objectives: The fifth edition of the WHO Classification of Tumors of the Central Nervous System divides grade 4 diffuse glioma based on IDH1 mutation in grade 4 astrocytoma, IDH-mutant and glioblastoma, IDH-wild type tumors. This study aimed to evaluate the IDH1 status in grade 4 diffuse glioma as well as its correlation with clinicopathological features and patient survival. To our knowledge, no Tunisian studies on the molecular profile of diffuse glioma have yet been published. Methods: This is a retrospective study including all cases of adult, grade 4 diffuse glioma collected in the pathology department of Habib Bourguiba hospital. Results: A total of 67 patients were included in the final analysis. The expression of IDH1 was positive in 22 cases (32%). IDH1-positive tumors were classified as grade 4 astrocytoma, IDH1-mutant while, 45 IDH1-negative tumors were classified as glioblastoma, IDH1-wild type tumors (68%). IDH1 expression was correlated with younger age (≤ 40 years old), frontal location, complete surgical resection and well-defined borders. IDH1-positive tumors were associated significantly with better prognosis. The 1-year overall survival (OS) for grade 4 astrocytoma, IDH1-mutant was 86% compared with 8% in glioblastoma, IDH1-wild type (p=0.008). Conclusion: Our study investigated IDH1 expression in grade 4 diffuse glioma and proved that grade 4 astrocytoma, IDH1 positive tumors displayed different characteristics with a more favorable outcome compared to glioblastoma, IDH1 negative. Thus, evaluation of IDH1 mutation should be standardized routinely not only as diagnostic marker but also to refine the prognostic classification of these tumors.