Expression and importance of serum MicroRNAs in prostate cancer

The study was to investigate the expression and clinical significance of serum microRNAs in prostate cancer. Illumina Human miRNA high-throughput chip was used to detect the serum microRNA expression in prostate tissues from 10 healthy subjects, 30 benign prostatic hyperplasia patients and 75 prostate cancer patients. Moreover, differentially expressed microRNAs were selected for further validation in 10 benign prostatic hyperplasia patients and 30 prostate cancer patients with real time fluorescent quantitative PCR. At last, the correlation between Gleason score of microRNA expression and clinical stages was evaluated. A total of 130 differentially expressed microRNAs were identified, of which 101 showed reduced expression and 29 displayed elevated expression. 22 microRNAs were chosen for validation by PCR, in which miR-29a, miR-625, miR-1323 and let-7d showed significantly down-regulated expression. Let-7d expression was related to Gleason score of prostate cancer (P<0.05), and the higher the Gleason score, the lower the let-7d expression was. microRNAs with their reduced expression, including miR-29a, miR-625, miR-1323 and let-7d, may act as anti-tumor genes in the occurrence and development of prostate cancer. Furthermore, let-7d may become a new marker for the early diagnosis and prognostic evaluation of prostate cancer.