10025-MPC-3 DIFFERENCE AMONG GENERATIONS IN PATIENTS WITH HISTONE H3-MUTATED GLIOMAS

Abstract OBJECT This study investigates clinical and molecular features, including the survival outcomes, of patients with histone H3-mutant gliomas and the differences among generations: children (-13 years), adolescence and young adult (AYA) (14-39 years), and older adult (40- years) patients. Particularly, we focused on the older adult cases. METHODS We collected pediatric and adult glioma cases harboring histone H3 mutations (K27M and G34R/G34V) enrolled in Kansai Network (118 cases) and retrospectively analyzed clinical characteristics and genetic status, including overall survival times (OS). Additionally, the differences between the older adult (40- years) and the younger generations (-39 years) were evaluated. RESULTS The older adult patients were not infrequently enrolled in the H3 K27-mutant glioma group (n = 47) (40-79 years old)), although H3 G34-mutant glioma cases belonged to around AYA generation (11-45 years old). Most popular location was brainstem in children (8/15, 53%) and thalamus in AYA (29/56, 52%), while cerebrum as well as brainstem and thalamus were common in the older adults (15/47, 32%; 15/47, 32%; 11/47, 24%). Histologically, diagnosis of non-GBM was not uncommon (63/105, 60%). There were no significant age-specific differences in genetic status (IDH1/2, TERT promoter, MGMT promoter, TP53, BRAF, FGFR1, EGFR). In general, tumor biopsy followed by radiation and chemotherapy was the main treatment regimen regardless of patient age (92/115, 80%). Particularly in the H3 K27-mutant gliomas, there was no statistically significant difference in OS among generations (median OS of children/AYA/older adult, 16.6/18.4/15.9 months). CONCLUSIONS We report clinicopathological features and survival outcomes of histone H3-mutated glioma patients in Kansai Network cohort. Histone H3 mutation could exist in the older adult cases with diffuse gliomas at cerebral location. There was a little difference in clinical and pathological features among generations. The prognosis of the older adults was as poor as those of children and AYA.