Exosomal microRNA in Predicting the Aggressiveness of Prostate Cancer in Chinese Patients

Prostate cancer (PCa) is the third most common male cancer in Hong Kong. While the use of serum PSA has greatly improved the proportion of patients diagnosed at localized /early stage, there are also problems of overdiagnosis and overtreatment. Unfortunately, there was still no ideal markers that could help to predict the aggressiveness of PCa, especially in Chinese population. Exosome is an important media for cell-cell interaction. The content of exomsomes, including microRNAs, are believed to have important roles in PCa development and progression, and might also serve as potential markers in PCa management. Therefore, investigators would like to explore the role of exosomal microRNA in the prediction of tumour aggressiveness in local Chinese PCa patients. This is a prospective study divided into two parts. Subjects will be recruited consecutively from two hospitals. In Part I of the study (Candidate exosomal microRNA discovery and selection), a total of 60 patients from three groups (non-cancer, pathologically insignificant cancer and significant cancer patients) will be recruited. First portion of urine will be collected from them. For Group 2\&3 patients, they are patients with clinically localized prostate cancer and planned for radical prostatectomy, urine will be collected before surgery for these two groups. Exosomal RNA will be extracted from urine and microRNAs expression profiles will be determined by next-generation sequencing. Candidate exosomal microRNAs that could differentiate pathological insignificant and significant PCa will be identified for Part II study. In Part II study (Candidate exosomal microRNAs validation), 180 patients with localized prostate cancer, planned for radical prostatectomy will be recruited. Urine will be again collected before surgery and the level of candidate exosomal microRNAs for each patient will be assessed. The diagnostic accuracy of these candidate exosomal microRNAs on predicting pathological insignificant cancer and also correlation with the final pathology will be assessed. The primary tasks for Part I study is the identification of potential exosomal microRNAs that could differentiate pathologically insignificant and significant PCa. The primary task for Part II study is the validation of the ability of those candidate exosomal microRNAs in differentiating pathological insignificant and significant PCa.