Really, it has been proven for decades that calcitonin, as well as other neuroendocrine markers (serotonin, chromogranin A, and enolase neurone specific antigen NSE), is highly expressed in prostate tissue and that the neuroendocrine differentiation of prostate cancer is generally associated with tumours progression and poor prognosis [9, 21]. This evidence concerns the gene CALCA and Familial prostate cancer.