PATH-40. CLINICAL CHARACTERIZATION OF H3K27M-MUTANT GLIOMAS

Abstract Diffuse midline gliomas, H3K27M-altered(DMGs) are a recently defined entity of gliomas, occur in midline, infiltrate diffusely and have poor prognosis. We reviewed our cases of DMGs to describe clinical, pathological, molecular characteristics, retrospectively. We detected 39 H3K27M-mutant cases of our 959 consecutive gliomas(4.1%). All H3K27M mutations were identified genetically. 23 datasets of these H3K27-mutant gliomas are available to detect their clinical, pathological, molecular characteristics. 5 young(8 - 18 y.o.) and 18 adult (28-80 y.o.) were included. All except one H3K27M-altered were WHO Grade III or IV pathologically. Most common location was thalamus(10/23, 43.4%), pons(6/23, 26.1%), brainstem(3/23, 13.0%). 2 non-midline gliomas were included. In this cohort, Median overall survival were 494 days in young patients, 464 days in adult patients. Current adjuvant chemotherapy and radiation-therapy have not prolonged poor prognosis of DMG patients. It is necessary to explore novel therapeutic targets.