OBJECTIVEExperimental evidence shows that microRNAs play an important role in the initiation and progression of human malignancies. The present study aimed to investigate the expressions of 6 microRNAs in prostate cancer (PCa) and their clinical significance.

METHODSWe investigated the expression profiles of 6 microRNAs (let-7g, let-7d, miR-98, miR-96, miR-182 and miR-183) using the method of locked nucleic acid (LNA)-modified oligonucleotide in situ hybridization (ISH) and the technology of tissue microarray (TMA) with the formalin-fixed paraffin-embedded (FFPE) specimens from 52 patients with PCa and 38 with benign prostatic hyperplasia (BPH). Then we analyzed the correlation among the expressions of the 6 microRNAs in PCa and their correlation with the Gleason score and clinical stages of PCa.

RESULTSCompared with BPH, the PCa patients showed decreased expressions of miR-98, let-7d and let-7g, and decreased expressions of miR-96, miR-182 and miR-183, with statistically significant differences between the two groups (P < 0.05). The positive rate of the 6 microRNAs was significantly correlated with the Gleason grades of PCa (P < 0.05), but not with the age and serum PSA concentration of the patients (P > 0.05). The expressions of miR-96 and miR-182 were correlated with the clinical stages of the tumor (P < 0.05). There was a positive correlation among the expressions of miR-96, miR-182 and miR-183 (P = 0.00, r = 0.41), as well as between the expressions of let-7d and let-7g (P = 0.00, r = 0.46) in the PCa tissues. And the expression of miR-98 was positively correlated with those of let-7d and let-7g (P = 0.00, r = 0.46).

CONCLUSIONThe expression profiles of the microRNAs let-7d, let-7g, miR-98, miR-96, miR-182 and miR-183 reflect the biological behavior of PCa to some extent, and might be important biomarkers for the early detection and prognostic assessment of prostate cancer.