Investigation of proteom profiles in prostate cancer with LC-MS-MS

Prostate cancer (PCa) is one of the most common cancer types observed in males around the worldwide and resulted in death in large proportions. The diagnosis of prostate cancer is based mainly on digital rectal examination, serum PSA (prostate specific antigen) measurement and biopsy. The biggest disadvantage of PSA is that it leads to false negative or false positive test results. Biopsy is not intended to be preferred with concerns that it may cause damage to organs and tissues by patients. In this study, biomarkers were determined to diagnose prostate cancer as an alternative to invasive techniques using LC-MS-MS. The proteins obtained from the urines of healthy and prostate cancer specimens were purified by applying acetone precipitation technique which had been kept in sterile tubes. After this step, by using the filter assisted sample preparation technique, the proteins were firstly broken up into the peptides by enzymatic digestion prior to MS analysis. The obtained peptides were analyzed by using LC-MS-MS and the protein profiles were examined mutually. The up-regulated and down-regulated proteins which may be associated with the cancer disease were detected. For the detected significant proteins, in addition to the relationship of these proteins to each other, the molecular functions, cellular, biological and reaction processes were investigated by string pathway analysis. Significant proteins between the two groups by Ingenuity Pathways Analysis (IPA) program were examined. Pyruvate kinase PKM and Kallikrein-11 proteins associated with prostate cancer were detected as biomolecular candidates. These results are very promising as a preliminary study, and LC-MS-MS technique is crucial to be clinically feasible after the validation phase of identified biomarkers. With this technique, the diagnosis of prostate cancer from urine in a short time and with high accuracy is very important in terms of establishing successful treatment programs by rapidly diagnosing cancers.