Based upon the co-localization of AR and CXCR7 proteins it is highly likely AR, CXCR7, and β-arrestin 2 form a ternary complex since β-arrestin 2 has been shown to bind both AR and CXCR7 in prostate-cancer cells [19,46,74,75]. Here, ACKR3 is linked to Familial prostate cancer.