Figure 3.

Early origin of recurrence from a grade II oligodendroglioma. Tumor evolution inferred from mutations in a primary 1p19q codeleted, IDH2 mutant low-grade oligodendroglioma and two tumor samples from a subsequent tumor recurrence from the same patient, resected years later (recurrence Y, recurrence G). The phylogenetic tree is derived from somatic mutations from exome sequencing of the tumor DNA samples. The length of each line in the phylogenetic tree is proportional to the number of mutations. The branch positions illustrate inferred points of evolutionary divergence among the samples. The IDH2 mutation is shared by all three samples whereas a different CIC mutation is found in the initial sample versus in the two tumor samples at recurrence.