Circulating microRNAs in plasma before and after radical prostatectomy

Abstract

PurposeMicroRNAs (miRNAs/miRs) as circulating biomarkers for prostate cancer have yet to be determined. We examined whether circulating miRNAs in plasma could be employed as biomarkers of disease among men treated for prostate cancer by radical prostatectomy (RP). MethodsThe expression of 17 preselected circulating miRNAs associated with prostate cancer (miR-381, -34a, -365, -122, -375, -1255b, -34b, -450b-5p, -885-5p, -1260, -150, -378, -671-3p, -148a, and -224) or high-grade prostate cancer (miR-28 and -100) in plasma at prostate biopsy was examined in pre- and post-RP plasma of prostate cancer patients using real-time PCR and compared using Wilcoxon signed-ranked test. Wilcoxon rank sum test was used to compare the expression of miRNAs in pre-RP plasma between pathologic tumor stage (T2 vs. T3) and Gleason score (6–7 [3 + 4] vs. ≥ 7 [4 + 3]) groups. Partial correlation coefficient between the expression of miRNAs in pre-RP plasma and serum prostate-specific antigen (PSA) level at RP, adjusting for age, was calculated. ResultsTwenty-nine men, aged 43 to 77 years, were included. Median follow-up time after RP was 55 days. There was no significant change in the expression of miRNAs in plasma from before to after RP. However, higher expression of miR-34a, -378, and 450b-5p in pre-RP plasma was observed among T3 compared to T2 patients (P values = 0.01). Overall, there were no statistically significant relationships observed between the expression of these circulating miRNAs and Gleason score and serum PSA at RP. ConclusionsThere was no significant change in the expression of circulating miRNAs in plasma from before to approximately 2 months after RP. This finding may be due to the lack of immediate effect RP may have on the expression of circulating miRNAs. However, higher expression of miR-34a, -378, and -450b-5p in plasma was found among patients with more advanced disease at RP. A longer follow-up time after RP is warranted to investigate RP's possible influence on circulating miRNAs among men treated for prostate cancer and to evaluate miRNAs’ diagnostic potential for prostate cancer.