IL1R1 and glioblastoma: To determine where within the tumor IL1B and its receptor (IL1R1) are expressed, we queried the IVY Glioblastoma Atlas Project (IVY GAP) database (https://glioblastoma.alleninstitute.org/) and found that IL1B and IL1R1 are predominantly transcribed in perinecrotic and perivascular regions, whereas the tumor bulk contains comparatively little expression (Figure 1F) (21).