Ki-67 labelling index of 3 WHO grade III tumours with RAS mutation was higher than that of other grade III tumours (average 29.2% (12.5–40%) vs 15.7% (3.6–50%), p = 0.04), and that of 2 anaplastic astrocytomas was higher than that of other anaplastic astrocytomas (average 37.5% (35–40%) vs 13.9% (3.6–30%), p = 0.0003). Here, MKI67 is linked to anaplastic astrocytoma.