ASSESSMENT OF MOLECULAR BIOMARKERS FOR BLADDER CANCER DIAGNOSIS, GRADING AND PROGNOSIS

Worldwide, bladder cancer is a very significant public health problem, in terms of prevalence, mortality and management for individuals and their families. Bladder cancer is the fourth most commonly diagnosed cancer in men and one of the heaviest cancers in terms of cost. Although transurethral resection of the bladder followed by intravesical instillation of live attenuated Bacillus Calmette–Guérin (BCG) is considered as the gold standard for patients with intermediate and high risk, only a small portion of patient responds to the BCG-therapy. Bladder cancer management is faced by the therapy failure, great side effects and some difficulties in histological classification. Accordingly, growing interest is given to the use of genetic, epigenetic and immunologic biomarkers for molecular signature characterization and tumor stratification. In Morocco, great efforts have been made to contribute to the improvement of management of bladder cancer and many studies were made to evaluate some genetic and epigenetic biomarkers. Generated data is of a great interest for characterization of bladder cancer tumors in Morocco and could be used for better management of this disease

The Evaluation of Vascular Endothelial Growth Factor A (VEGFA) and VEGFR2 Receptor as Prognostic Biomarkers in Bladder Cancer

Vascular endothelial growth factor (VEGF) and its receptors (VEGFR1 and VEGFR2) are the most important tissue factors involved in tumor growth and angiogenesis. The aim of this study was to evaluate the promoter mutational status of VEGFA and the expression levels of VEGFA, VEGFR1, and VEGFR2 in bladder cancer (BC) tissues and to correlate the results with the clinical–pathological parameters of BC patients. A total of 70 BC patients were recruited at the Urology Department of the Mohammed V Military Training Hospital in Rabat, Morocco. Sanger sequencing was performed to investigate the mutational status of VEGFA, and RT-QPCR was used to evaluate the expression levels of VEGFA, VEGFR1, and VEGFR2. Sequencing of the VEGFA gene promoter revealed the presence of −460T/C, −2578C/A, and −2549I/D polymorphisms, and statistical analyses showed a significant correlation between −460T/C SNP and smoking (p = 0.02). VEGFA and VEGFR2 expressions were significantly up-regulated in patients with NMIBC (p = 0.003) and MIBC (p = 0.03), respectively. Kaplan–Meier analyses showed that patients with high VEGFA expression had significantly longer disease-free survival (p = 0.014) and overall survival (p = 0.009). This study was very informative, showing the implication of VEGF alterations in BC, suggesting that VEGFA and VEGFR2 expressions could be promising biomarkers for the better management of BC

Exploring urine sediments as a non-invasive method for DNA methylation detection in bladder cancer

Abstract Background The main epigenetic event occurring during the bladder carcinogenesis process is DNA methylation, affecting genes involved in various metabolic pathways and cell regulation. The use of biological fluids such as urine sediments could be used as a non-invasive approach to enhance bladder cancer management. In this study, we aim to determine the promoter methylation status of a panel of genes in bladder cancer on tumor biopsies and urine sediments to evaluate the usefulness of urine samples as a non-invasive approach for methylation status assessment. Methods Using the methylation-specific PCR technique, we explored the promoter methylation status of hTERT, TWIST1, VIM and NID2 genes in 40 tumor biopsies and their paired urine samples from Moroccan bladder cancer patients. Results In this study, bladder tumors showed promoter hypermethylation frequency of individual genes as 90%, 85%, 62.5% and 72.5% in TWIST1, hTERT, NID2 and VIM genes, respectively. Interestingly, the specificity of methylation detection in urine samples was 100% and the sensitivity to detect hypermethylation of TWIST1, hTERT, NID2 and VIM genes reached 91.7%; 97.1%; 84% and 82.8%, respectively. Conclusions Our results clearly show that the assessment of promoter hypermethylation in urine samples is highly specific and has high sensitivity. Furthermore, urine sediments would be a useful approach to detect the DNA methylation status of genes and its potential association with bladder cancer development

Immune checkpoint and telomerase crosstalk is mediated by miRNA-138 in bladder cancer

Tumor recurrence and progression in non-muscle invasive bladder cancer (NMIBC), therapy failure, and severe side effects in muscle invasive bladder cancer (MIBC) are the major challenges in the clinical management of bladder cancer (BC). Here, we identify new molecular targetable signatures to improve BC patients' stratification and the outcome of current immunotherapies. In a prospective cohort of 70 BC patients, we assessed the genetic and molecular regulation of TERT in maintaining telomere length in parallel to immune checkpoint and microRNA expression. TERT was undetectable in healthy bladder tissues but upregulated in invasive BC stages and high tumor grade. Its expression was linked with the combined effect of the C250T mutation and THOR hypermethylation, associated with progressing tumors and maintaining of telomere length. In the same cohort, PD-L1 scored highest in NMIBC, while PD-L2 was upregulated in MIBC. We also show that miR-100-5p and 138-5p were highly expressed in healthy bladder specimens and cell line, while expression decreased in the BC tissues and BC cell lines. In line with the binding prediction for these miRNAs on target genes, miRs 100-5p and 138-5p expression strongly inverse correlated with TERT, PD-L1, and PD-L2 expression, but not PD1. We identify a loop involving TERT, PD1-ligands, and miR-138-5p in BC, that might represent not only a useful biomarker for improved diagnosis and patients' stratification but also as a promising axis that might be therapeutically targetedin situ.</p