Collectively, PSAP and its derivative Sap C play pivotal roles in PCa initiation, progression, and transition to CRPC by engaging in positive feedback regulation of the AR signaling pathway (including upregulating AR expression, promoting its nuclear translocation and phosphorylation), and activating downstream pro-survival (e.g., PI3K/Akt), pro-migration/invasion (e.g., MAPK/JNK, uPA/uPAR) pathways. The gene discussed is MAPK8; the disease is posterior cortical atrophy.