The density of activated microglial cells (HLA-DR-positive cells) within the tumor was positively correlated with the pre-operative seizure frequency (0.834, p < 0.001), the duration of epilepsy (0.631, p = 0.001), and the age at surgery (0.521, p = 0.006); positive correlation was also observed with the IL-1β IRS in both tumor and peritumoral cortex (0.838, p < 0.001; 0.535, p = 0.04); Additional file 4: Figure S1A–C. This evidence concerns the gene IL1B and epilepsy.