GDF15 and posterior cortical atrophy: However, only SLC12A2 (P = 4.81e−4), DDAH1 (P = 4.99e−4), NDRG1 (P = 0.005), APOE (P = 0.011), YWHAZ (P = 0.002), and GDF15 (P = 0.014) displayed significant upregulated gene expression levels when comparing PCa vs. normal prostate gland (Fig. 2a, black boxes).