CD8A and posterior cortical atrophy: In our cohort, we found that CD8+ PD-1+ T cells comprised a ~5-fold greater proportion of all T cells in BICs from HGG than LGG PCa (Mann-Whitney U test, P = 2.4 ×10−6, Fig 6e; Extended Data Fig. 6e) and that Tpex cells were ~7-fold more prevalent in HGG BICs (Mann-Whitney U test, P = 1.1 × 10−6, Fig. 6f).