Temporal progression of tumor formation in FMC mice. (A) GFAP immunostaining increased over time in FMC compared with FF optic nerves. (B) Increased percentages of S100β+ astrocytes were observed in FMC relative to FF optic nerves by 6 weeks of age, expressed as the %S100β+ cells relative to FF controls. S100β+ cells continued to increase thereafter. (C) Optic nerves and corresponding optic nerve volumes increased in FMC mice between 9 weeks and 12 weeks of age (n = 8). At least 6 mice per group were included for each time point. Blue lines = FF, red lines = FMC, *P ≤ .05,**P ≤ .01, P ≤ .001. Graph denotes mean ± SEM.