Cysteine-rich secretory protein-3: a potential biomarker for prostate cancer

Electronic profiling of publicly available expressed sequence tag databases identified a gene, cysteine-rich secretoryprotein-3 (CRISP-3), that is up-regulated in prostate cancer, and of which the expression is relatively prostate-specific. The objective of this study was to examine the potential of CRISP-3 as a biomarker for prostate cancer. In transient transfection studies, CRISP-3 was found to be a secretory protein. Using a multiple tissue dot blot experiment, CRISP-3 transcript was identified in a limited number of human tissues including the prostate. In situ hybridization experiments indicated that CRISP-3 mRNA is epithelial-specific and is up-regulated in prostate adenocarcinoma compared with benign prostate tissue. CRISP-3 mRNA overexpression in cancer was confirmed using quantitative real-time reverse-transcription-PCR using benign prostatic epithelia and adenocarcinoma (in 5 of 5 cases) isolated by laser capture microdissection, as well as bulk tissues (in 20 of 23 cases) from surgically resected human prostates. These findings suggest that CRISP-3 is a potential biomarker for prostate cancer.