Then it was shown to be expressed in normal tissues as well as malignant tissues. It is an important regulator of smooth muscle tone and calcium absorption (39). Studies have shown that parathyroid hormone-related protein (PTHrp) is vital in inducing EMT in DU145 prostate cancer cells overexpressing PTHrp [ref9]. This hormone enhances cancer progression by binding to a cell surface receptor or a nuclear receptor. Therefore its mode of action occurs through paracrine, autocrine and intracrine pathways [ref24]. PTHrp, through its receptor, has been confirmed to play a role in prostate-to-bone metastasis. In vivo studies in mouse models demonstrated that human cell lines transfected with (PTHrp) exhibited skeletal cancer progression. Thus, there is a direct correlation between the expression level of PTHrp and bone metastases from the prostate [ref