Background and purpose:Liquid biopsy is a kind of blood, urine and other non-solid biologi-cal tissue sampling analysis, mainly for malignant tumor diagnosis, monitoring and predicting its prognosis. In this research, we optimized the extraction of miRNA in urine, established a standardized means of liquid biopsy, screened and verified the miRNA markers in patients with bladder cancer.Methods:From Jan. 2014 to Sept. 2015, we used miRNA microarray in six patients with bladder cancer and six healthy controls. Samples of 78 cases of bladder cancer and 23 healthy controls were tested by real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) to verify the relationship between miRNA markers in liquid biopsy and clinical pathological parameters. The diagnostic value of miRNA markers was also analyzed and compared.Results:We screened 10 miRNAs differential expression in urine. Combined with previous literature, we selected 20 miRNAs to verify their expression levels in bladder cancers and healthy controls. miR-509-5p/miR-124 ratio in the urine was found higher in patients with bladder cancer than in healthy controls (P<0.0001). With the rise of miR-509-5p/miR-124 ratio in urine, tumor stage and grade were also increased (P=0.003). When the cutoff was set at 0.41, the diagnostic sensitivity and specificity of miR-509-5p/miR-124 ratio were 73.1% and 82.6%, respectively. The AUC of miR-509-5p/miR-124 ratio to detect bladder cancer was 0.864, higher than that of urinary exfoliated cells (P=0.0002).Conclusion:We optimized the extraction of miRNAs in urine,established a standardized liquid biopsy of miRNA markers. The miR-509-5p/miR-124 ratio could be an ideal diagnos-tic marker for bladder cancer.

【Objective】 To introduce a surgical technique modified by our center, the establishment of a robot-assisted radical prostatectomy (RARP) channel with extraperitoneal three-port method, and discuss its methods, skills, safety and efficacy. 【Methods】 Clinical data of 21 patients with early and intermediate prostate cancer treated with this surgery during Aug.2022 and Jun.2023 were retrospectively analyzed.Surgical time, intraoperative bleeding volume, postoperative complications, drainage tube retention time, postoperative hospital stay, and follow-up results were observed. 【Results】 All 21 cases of surgery were successfully completed by the same surgeon, without peritoneal rupture or addition of auxiliary holes.The time to establish the extraperitoneal gap and install robotic arm was 20.2 (16.0-28.0) min, the operation time was 107.0(60.0-161.0) min, the amount of intraoperative bleeding was 52.8 (31.0-121.0) mL.All patents resumed eating and drinking the next day after operation.The drainage tube indwelling time was 3.9 (2.0-6.0) d, and the postoperative hospital stay was 4.9 (3.0-7.0) d.No serious complications occurred.The urinary catheter was removed 10 days after operation.One month after operation, 20 patients (95.2%) achieved satisfactory urinary control.The postoperative pathology was prostate adenocarcinoma in all cases, with negative margins, and the prognostic grouping of ISUP was 2 cases in group 1, 6 cases in group 2, 10 cases in group 3, 2 cases in group 4, and 1 case in group 5. 【Conclusion】 RARP by extraperitoneal three-hole method is safe and feasible, with exact establishment of extraperitoneal space, few collisions between instruments, low surgical costs, fast postoperative intestinal recovery, aesthetic incision, and satisfactory recovery of urinary control.