Profiling of the calcitonin-calcitonin receptor axis in primary prostate cancer: clinical implications and molecular correlates.

Expression of the neuroendocrine peptide calcitonin (CT) and its receptor (CTR) is frequently elevated in prostate cancers (PCs), and activation of the CT-CTR axis in non-invasive PC cells induces an invasive phenotype. We aimed to link CT/CTR expression in prostate specimens to clinicopathological parameters of PC. We analyzed CT and CTR expression in cohorts of benign prostates and primary PCs with/without metastatic disease by immunohistochemistry. Furthermore, we correlated CT/CTR expression with several clinicopathological parameters. CT/CTR immunostaining in benign prostate acini was predominantly localized to basal epithelium. However, this spatial specificity was lost in malignant prostates. PC sections displayed a remarkable increase in cell populations expressing CT/CTR and their staining intensity. Tumors with higher CT/CTR expression consistently displayed metastatic disease and poor clinical outcome. High CT/CTR expression in primary prostate tumors may serve as a prognostic indicator of disease aggressiveness and poor clinical outcome.