Overall, our studies add to the growing body of evidence thatopiorphin-encoding genes play a role in cancer development and progression.PROL1 is essential for establishment and growth oftumors in mice injected with LNCaP cells, and we provide evidence thatPROL1 has a possible role in progression towards a moreinvasive, metastatic and castration resistant prostate cancer (PrCa). Here, OPRPN is linked to pure red-cell aplasia.