While IDH1/2 mutations and G-CIMP are commonly retained during tumor recurrence, recent work has uncovered losses of the IDH1 mutation in a subset of secondary glioblastomas.
In astrocytomas, genomic alterations in effectors of cell-cycle progression correlated with aggressive disease independent of IDH mutation status, arose preferentially in enhancing tumors (44% vs. 8%, <i>P</i> < 0.001), were associated with rapid disease progression following tumor recurrence (HR = 2.6, <i>P</i> = 0.02), and likely preceded the acquisition of alkylating therapy-associated somatic hypermutation.
Mutations in IDH1 or IDH2 were associated with longer overall survival (P=0.028) and were independently associated with a longer time to tumor recurrence after intrahepatic cholangiocarcinoma resection in multivariate analysis (P=0.021).