Title: Direct quantitative detection for cell-free miR-155 in urine: a potential role in diagnosis and prognosis for non-muscle invasive bladder cancer
Abstract: // Xin Zhang 1 , Yanli Zhang 2 , Xinfeng Liu 2 , Aiju Fang 3 , Jinfeng Wang 1 , Yongmei Yang 1 , Lili Wang 1 , Lutao Du 1 , Chuanxin Wang 1 1 Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan 250012, China 2 Department of Clinical Laboratory, Traffic Hospital of Shandong Province, Jinan 250031, China 3 Department of Pathology, Traffic Hospital of Shandong Province, Jinan 250031, China Correspondence to: Chuanxin Wang, e-mail: [email protected] Keywords: cell-free, miR-155, urine, non-muscle invasive bladder cancer, biomarker Received: July 07, 2015 Accepted: November 21, 2015 Published: December 02, 2015 ABSTRACT High recurrence rates of non-muscle invasive bladder cancer (NMIBC) in patients require lifelong testing and monitoring. The aim of this study is to develop a simplified RT-qPCR method (RT-qPCR-D) which directly quantifies cell-free miR-155 in urine without RNA extraction, and assess it as a potential tool in NMIBC detection. A pilot study including 60 urine samples was used to investigate the feasibility of RT-qPCR-D in detecting cell-free miR-155. Then, miR-155 levels were quantified in a large independent cohort of urine from 162 NIMBC patients, 76 cystitis patients, and 86 healthy donors using the RT-qPCR-D method. Changes of cell-free miR-155 before and after operation were also analyzed in 32 NIMBC patients. In pilot study, we found a significant linear association between RT-qPCR and RT-qPCR-D in urinary miR-155 detection. Both methods showed cell-free miR-155 were significantly increased in NMIBC patients, and could reflect their expression in tissues. Then, the increased expression of cell-free miR-155 was successfully validated in 162 NIMBC patients when compared with cystitis patients and healthy donors. Moreover, it distinguished NMIBC patients from others with 80.2% sensitivity and 84.6% specificity, which was superior to urine cytology. Cell-free miR-155 correlated with NMIBC stage and grade, and was an independent factor for predicting recurrence and progression to muscle invasion. In addition, cell-free miR-155 was significantly decreased after NMIBC patients underwent transurethral bladder resection. In conclusion, detection of cell-free miR-155 in urine using RT-qPCR-D is a simple and noninvasive approach which may be used for NMIBC diagnosis and prognosis prediction.