In prostate and breast epithelial cells, the regulation of Endoglin expression contributes to the control of cell motility by PRH.3 Moreover, over-expression of PRH in prostate cancer cells and breast cancer cells inhibits cell migration and inhibits the ability of prostate cancer cells to penetrate a layer of endothelial cells in in vitro extravasation experiments.3 Here we show that PRH is hyper-phosphorylated in BPH, prostatic adenocarcinoma and prostate cancer cell lines and that PRH phosphorylation in prostate cells is dependent on CK2 activity. This evidence concerns the gene HHEX and breast cancer.