Notably, we observed an abundance of Aif1, Met, and Fosl1 expressing cells not exclusively in hypoxic regions but also in the perivascular space of Pdgfbret/ret glioma sections, indicating a putative opportunistic occupation and exploitation of this glioma niche vacated by pericytes (Figs. 7D and S14C). This evidence concerns the gene FOSL1 and central nervous system cancer.