CD163 and meningioma: Comparing the AKT1 E17K tumour tissues to the NF2-negative grade I meningiomas showed that AKT1 E17K mutants contained significantly fewer CD68 macrophages (7.4 vs. 10.7%; p = 0.036; Figure 3) and CD163-positive cells (8.4 vs. 12.9%; p = 0.049; Figure 4) compared to NF2 meningiomas, supporting the flow cytometry data suggesting that genotype may influence immune cell filtration over the course of tumour development.