Kosugi et al. analyzed 28 meningioma tissues arising in two different locations, highlighting how an immunologically reclusive microenvironment exists in cavernous sinus (CS) meningiomas, in comparison with convexity meningiomas [18]; thus, tumor-infiltrating lymphocytes (TILs), regulatory T cells, HIF-1α, VEGF-A, and VEGFRs-1 & 2 expression, and tumor-associated macrophages (TAMs) were significantly fewer in CS meningiomas compared with convexity meningiomas. Here, VEGFA is linked to Cowden syndrome 1.