BACKGROUNDAlthough the introduction of serum prostate-specific antigen (PSA) measurements into clinical practice has revolutionized the care of patients with prostate cancer, there are well-recognized limitations of PSA, and there is a critical need to identify additional prostate cancer biomarkers to assist in early detection and prognosis. In this regard, high resolution proteomic technology has the unexceptionable superiority to find those high abundance biomarkers. The purpose of this study was to search new tumor markers by proteomic technology.

METHODSThe proteins in conditioned medium (CM) of BPH-1 and LNCaP cells were profiled by two-dimensional electrophoresis and identified by matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS). The corresponding mRNA levels of some identified proteins were analyzed by RT-PCR.

RESULTSTotally 11 differentially expressed proteins (6 up-regulated including creatine kinase, brain (CKB), triosephosphate isomerase 1 (TPI1), isocitrate dehydrogenase 2 (IDH2) and 5 down-regulated including glutathione S-transferase pi (GST-pi)) in the CM were identified using MALDI-TOF-MS and database search. The expression pattern between mRNA and CM protein levels of CKB, IDH2, TPI1 and GST-pi in BPH-1 and LNCaP was similar.

CONCLUSIONWe proved a feasible and effective way to search new tumor markers by a proteomics-based strategy and identified 11 potentially useful proteins in CM of BPH-1 and LNCaP cells to distinguish prostate cancer from benign prostatic hypertrophy.