To verify whether GDPP was truly present as a secreted protein and to determine its levels in various PCa cell lines, we performed western blot analysis and confirmed the exogenous expression of GDPP and mGDF15 in the culture media of LNCaP, 22Rv1, PC3 and DU145 cells, whereas only pro-GDF15 expression was detected in the whole-cell lysate (WCL) of LNCaP, 22Rv1, and PC3 cells (Fig. 2B). Here, GDF15 is linked to posterior cortical atrophy.