GDF15 and posterior cortical atrophy: Immunohistochemistry of serial sections of PCa (GS6), stained with antibodies directed against GDF-15, PD-L1, CD68, or CD163, exhibit luminal excrescences of epithelial cells with positive IR for GDF-15 and PD-L1, and presence of CD68+ MΦ (Figure 7B,C), but not of CD163+ MΦ (Figure 7D).