Prostate cancer tissue proteomics

Prostate cancer (PCa) is a non-cutaneous malignancy that is the most frequent cancer found in males worldwide, and its mortality rate is increasing every year. Although, PCa grows slowly and is not a threat to survival, advanced PCa, metastatic PCa, is aggressive form of PCa and can spread to other organs, resulting in the 5-year survival rate dropping to 30%. However, there are no molecular markers for advanced and/or aggressive PCa, and it is an urgent clinically need to find biomarkers for prognosis and prediction of advanced PCa. Here, we used mass spectrometry-based proteomics to discover new biomarkers for prognosis and prediction of advanced PCa in tissue obtained from PCa patients who were diagnosed with T2, T3 and metastasis in regional lymph nodes. We identified 1,904 proteins and 1,673 proteins were quantified from PCa tissues, respectively. In particular, 344 differentially expressed proteins (DEP) of which 124 were up-regulated and 216 were down-regulated were listed. From PLS-DA score plotting using SIMCA P+ software and GO and KEGG enrichment analysis by DAVID, we also propose SRM, NOLC1, and PTGIS, which we found through this proteomics analysis, as representing new protein biomarkers for diagnosis of advanced PCa. The proteomics results were verified by immunoblotting assay in metastatic PCa cell-lines and indirect ELISA in prostate specimens. In particular, SRM is significantly increased depending on cancer progress stages, so the possibility of biomarker for prognosis and prediction of advanced PCa is confirmed.