Activating Telomerase TERT Promoter Mutations and Their Application for the Detection of Bladder Cancer.

This review summarizes state-of-the-art knowledge in early-generation and novel urine biomarkers targeting the telomerase pathway for the detection and follow-up of bladder cancer (BC). The limitations of the assays detecting telomerase reactivation are discussed and the potential of transcription-activating mutations in the promoter of the TERT gene detected in the urine as promising simple non-invasive BC biomarkers is highlighted. Studies have shown good sensitivity and specificity of the urinary TERT promoter mutations in case-control studies and, more recently, in a pilot prospective cohort study, where the marker was detected up to 10 years prior to clinical diagnosis. However, large prospective cohort studies and intervention studies are required to fully validate their robustness and assess their clinical utility. Furthermore, it may be interesting to evaluate whether the clinical performance of urinary TERT promoter mutations could increase when combined with other simple urinary biomarkers. Finally, different approaches for assessment of TERT promoter mutations in urine samples are presented together with technical challenges, thus highlighting the need of careful technological validation and standardization of laboratory methods prior to translation into clinical practice.

Development of a Sensitive Digital Droplet PCR Screening Assay for the Detection of GPR126 Non-Coding Mutations in Bladder Cancer Urine Liquid Biopsies.

Recent whole-genome sequencing studies identified two novel recurrent mutations in the enhancer region of GPR126 in urothelial bladder cancer (UBC) tumor samples. This mutational hotspot is the second most common after the TERT promoter in UBC. The aim of the study was to develop a digital droplet PCR screening assay for the simultaneous detection of GPR126 mutations in a single tube. Its performance combined with TERT promoter mutation analysis was evaluated in urine of healthy volunteers (n = 50) and patients with cystitis (n = 22) and UBC (n = 70). The developed assay was validated using DNA constructs carrying the studied variants. None of the mutations were detected in control and cystitis group samples. GPR126 mutations were observed in the urine of 25/70 UBC patients (area under the ROC curve (AUC) of 0.679; mutant allele fraction (MAF) of 21.61 [8.30-44.52] %); TERT mutations-in 40/70 (AUC of 0.786; MAF = 28.29 [19.03-38.08] %); ≥1 mutation-in 47/70 (AUC of 0.836)). The simultaneous presence of GPR126 and TERT mutations was observed in 18/70 cases, with no difference in MAFs for the paired samples (31.96 [14.78-47.49] % vs. 27.13 [17.00-37.62] %, p = 0.349, respectively). The combined analysis of these common non-coding mutations in urine allows the sensitive and non-invasive detection of UBC.

Urine TERT promoter mutations-based tumor DNA detection in patients with bladder cancer: A pilot study.

Telomerase reverse transcriptase (TERT) promoter mutations are the most frequent genetic events in bladder cancer (BC). The aim of the present pilot study was to evaluate the diagnostic potential of urine TERT promoter mutations-based liquid biopsy in patients with an ongoing oncological process, as well as in post-resection patients at risk of BC recurrence. A total of 60 patients were enrolled, of whom 27 patients had histologically proven BC; 23 had no signs of BC (control group); and 10 patients underwent transurethral malignancy resection 3-6 months prior to urine donation ('second look' group). Urine TERT promoter mutations were detected using Droplet Digital PCR. Receiver operating characteristic curve analysis revealed significant diagnostic power of the present approach (area under the curve: -0.768). At the cut-off value of tumor DNA fraction 0.34%, the sensitivity and specificity were 55.56 and 100%, respectively. In the positive samples, tumor DNA fraction varied significantly from 0.59 to 48.77%. In the 'second look' group, tumor DNA was detected in 4/10 patients, highlighting the possibility of BC recurrence with its fraction ranging only from 0.90 to 6.61%. Therefore, urine TERT promoter mutations-based liquid biopsy appears to be a promising tool for BC diagnosis and surveillance. The main study will include recruitment of additional patients, extension of the mutation panel, prolonged follow-up of the post-resection patients, as well as screening of industrial workers exposed to specific carcinogens.

Risk factors for urethral stricture and/or bladder neck contracture after monopolar transurethral resection of the prostate for benign prostatic hyperplasia.

OBJECTIVE:: To identify risk factors for urethral stricture and/or bladder neck contracture after transurethral resection of benign prostatic hyperplasia. MATERIALS AND METHODS:: We performed a retrospective analysis of 402 patients, which underwent a monopolar transurethral resection of the prostate in the urology clinic of Sechenov First Moscow State Medical University for prostatic hyperplasia during the period 2011-2014. Urethral stricture and (or) bladder neck contracture in the postoperative period were diagnosed in 61 (15.27%) patients; 34 patients (8.6%) had urethral stricture, 20 (4.97%) bladder neck contracture, and 7 (1.7%) had a combination of urethral stricture and bladder neck contracture. In 341 of cases (84.73%), no late postoperative complications were observed. A total of 106 of the 341 patients met the inclusion criteria, hence, containing all the information necessary for analysis such as the volume of the prostate, the duration of the surgery, the size of the endoscope, data on concomitant diseases, analysis prostatic secretion, and so on. Thus, two groups were formed. Group 1 (106 patients) is the control group in which urethral strictures and/or bladder neck contractures did not occur in the long-term postoperative period and group 2 (61 patients), in which was observed the formation of these complications. To calculate the statistical significance of the differences for categorical data, Fisher criterion was used. For quantitative variables, in the case of normal data distribution, an unpaired t-test or one-way analysis of variance was used; for data having a distribution different from normal, a Mann-Whitney rank test was used. RESULTS:: Regression analysis established the significance of the influence of four factors on the development of scar-sclerotic changes of urethra and bladder neck: the tool diameter 27 Fr ( p < 0.0001), presence of prostatitis in past medical history ( p < 0.0001), prostate volume ( p = 0.003), and redraining of the bladder ( p = 0.0162). CONCLUSION:: The relationship between the diameter of the instrument, presence of chronic prostatitis in anamnesis, increased volume of the prostate, and repeated drainage of the bladder using the urethral catheter with the risk of developing scar-sclerotic changes in the urethra and/or bladder neck are statistically reliable and confirmed as a result of regression analysis.