Our findings raise the possibility that the presence of osteocalcin in the bone micro-environment potentially creates paracrine signaling pathways that might explain the propensity of CRPC to metastasize to bone [53]; and expression of osteocalcin in malignant prostate cell lines and prostate cancer specimens potentially leads to autocrine activation of GPRC6A [54]. This evidence concerns the gene GPRC6A and Familial prostate cancer.