CTLs can be identified in CyCIF data based on expression of the cytolytic protease granzyme B (GZB) and we found that CD8+ PD-1+ GZB+ cells comprised up to 0.9% of all T cells in PCa specimens and were almost 2-fold more abundant in HGG than LGG PCa (median of total number of CTLs divided by all T cells of ~3 × 10−3 and ~4 × 10−4, respectively; Mann-Whitney U tests, P = 0.029, Extended Data Fig. 6b). This evidence concerns the gene GZMB and posterior cortical atrophy.