Urine exosomal lncRNAs as novel biomarkers for early diagnosis of bladder cancer based on microarray differential expression profiling

Purpose We aimed to exploit a urine exosomal long non-coding RNAs (lncRNAs) fingerprint to facilitate the early diagnosis of bladder cancer. Methods Microarray differential expression profiling of lncRNAs was for the first time employed in urine exosomes from 10 non-muscle-invasive bladder cancer (NMIBC) patients and 10 healthy controls to screen out candidate exosomal lncRNA biomarkers, which were then verified by quantitative real-time polymerase chain reaction in three independent phases including bladder cancer cells, culture fluid and 200 NMIBC participants. Logistic regression was performed to construct a diagnostic model-the diagnostic potency of which was assessed. Results The profile of three exosome-derived lncRNAs (CCDC148-AS1, XLOC_006419, and RP5-1148A21.3) was screened and further verified to be notably over-expressed in NMIBC patients and bladder cancer cell lines, and exhibited area under the receiver-operating characteristic curve values of 0.873, 0.825, and 0.834, respectively, in training, validation, and double-blind validation phases. The profile was superior to urinary cytology in discriminating NMIBC from healthy controls (P < 0.0001). A significant correlation existed between a higher level of CCDC148-AS1 and a higher tumor grade (P < 0.001), and up-regulated CCDC148-AS1 as well as XLOC_006419 were statistically related with tumor node metastasis stage (P = 0.004 and P = 0.031, respectively). These three identified lncRNAs were confirmed to originate from bladder cancer cells and be packaged within exosomes, thus staying sufficiently stable in urine. Conclusions Tumor-originated urine exosomal lncRNAs, as fingerprint in NMIBC, exhibited satisfying clinical significance in early diagnosis of bladder cancer.