When we performed immunostaining of eight GBM biospecimens with the mouse monoclonal anti-GPR133 antibody and the anti-CA9 antibody, we observed that in 7/8 samples GPR133 colocalized with CA9 in hypoxic PPN regions (Figures 2di–iii and Supplementary Figure 3aii). This evidence concerns the gene ADGRD1 and glioblastoma.