To investigate the biological role of GDPP in various PCa cell processes, we used siRNA to knockdown GDF15 expression in PC3, which was originally derived from the BM site of a CRPC patient in which GDF15 is moderately expressed, and DU145, which was derived from the brain metastasis site of a CRPC patient in which GDF15 exhibited low expression. The gene discussed is GDF15; the disease is posterior cortical atrophy.