Prediction of recurrence of non-muscle invasive bladder cancer: The role of androgen receptor and miRNA-2909.

AIM: The exact role of androgen receptor (AR) and miR-2909 in non-muscle invasive bladder cancer (NMIBC) remains controversial. Our aim is to assess the relationship between NMIBC recurrences with AR expression and miRNA-2909. PATIENTS AND METHODS: This prospective controlled cohort study included 99 male patients with NMIBC (Ta-T1) who were treated by transurethral resection and 50 male patients as healthy control. We quantified blood AR messenger RNA variants 1 and 2 (AR1, AR2) and plasma miRNA-2909 with real-time quantitative polymerase chain reaction and the full length AR (AR-FL) using enzyme-linked immunosorbent assay in serum samples. In addition, AR1 and AR2 expression in tumor as well as normal tissues were analyzed. Kaplan-Meier survival curves and multivariate Cox analysis were used to identify independent predictors of recurrence-free survival. RESULTS: In comparison to control group, blood AR1, AR2, and serum AR-FL expression were significantly lower in the NMIBC group compared to plasma miRNA-2909 expression that was significantly higher in the control group. Blood AR1, AR2, and serum AR-FL were significantly correlated with higher tumor stage (pT1) while plasma miRNA-2909 was not. The median survival time (months) was significantly better for higher blood AR1 (34 vs. 21; P = 0.03), lower plasma miRNA-2909 (29 vs. 8; P <0.001), lower AR2 in normal tissues (32 vs. 22; P = 0.007). On multivariate analysis, serum free testosterone (hazards ratio [HR]: 8.9; 95% CI: 1.8-45.1; P = 0.008), serum AR1 (HR: 0.5; 95% CI: 0.3-0.9; P = 0.02), and plasma miRNA-2909 (HR: 5.8; 95% CI: 2.3-14.7; P = 0.0002), and tissue AR2 (HR: 2.6; 95% CI: 1.4-4.7; P = 0.002) were independent predictor for NMIBC recurrence. CONCLUSIONS: Blood and tissue levels of AR expression have a potential significant effect on NMIBC recurrence. Further studies are recommended to establish its exact role.