Histologic Grading of Bladder Tumors: Using Both the 1973 and 2004/2016 World Health Organization Systems in Combination Provides Valuable Information for Establishing Prognostic Risk Groups

Uncovering the epidemiology of bladder cancer in the Arab world: A review of risk factors, molecular mechanisms, and clinical features

Objective

Bladder cancer (BC) is a significant public health concern in the Middle East and North Africa, but the epidemiology and clinicopathology of the disease and contributors to high mortality in this region remain poorly understood. The aim of this systematic review was to investigate the epidemiological features of BC in the Arab world and compare them to those in Western countries in order to improve the management of this disease.

Methods

An extensive electronic search of the PubMed/PMC and Cochrane Library databases was conducted to identify all articles published until May 2022, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. A total of 95 articles were included in the final analysis after title, abstract, and full-text screening, with additional data obtained from the GLOBOCAN and WHO 2020 databases.

Results

Most of the included articles were case-control studies examining the risk factors and molecular mechanisms of BC. These studies originated from 10 different countries, with Egypt being the most active contributor. While BC in the Arab world shares some common risk factors with Western countries, such as smoking and occupational exposure, it also exhibits unique features related to schistosomiasis. The high mortality rates in this region are alarming and can be attributed to various factors, including the prevalence of smoking, the impact of schistosomiasis, a combination of genetic and socioeconomic factors, treatment shortages, and limited access to care or inadequate assessment of the quality of care.

Conclusion

Despite the relatively low incidence of BC in Arab countries, the mortality rates are among the highest worldwide. BC tends to be more aggressive in the Arab world, making it essential to implement strategies to address this burden.

Biological and clinical perspectives of TERT promoter mutation detection on bladder cancer diagnosis and management

The telomerase reverse transcriptase (TERT) promoter mutations are associated with increased TERT mRNA and TERT protein levels, telomerase activity, and shorter but stable telomere length. TERT promoter mutation is the most common mutation that occurs in approximately 60-80% of patients with bladder cancer. The TERT promoter mutations occur in a wide spectrum of urothelial lesions, including benign urothelial proliferation and tumor-like conditions, benign urothelial tumors, premalignant and putative precursor lesions, urothelial carcinoma and its variants, and nonurothelial malignancies. The prevalence and incidence of TERT promoter mutations in a total of 7259 cases from the urinary tract were systematically reviewed. Different platforms of TERT promoter mutation detection were presented. In this review, we also discussed the significance and clinical implications of TERT promoter mutation detection in urothelial tumorigenesis, surveillance and early detection, diagnosis, differential diagnosis, prognosis, prediction of treatment responses, and clinical outcome. Identification of TERT promoter mutations from urine or plasma cell-free DNA (liquid biopsy) will facilitate bladder cancer screening program and optimal clinical management. A better understanding of TERT promoter mutation and its pathway would open new therapeutic avenues for patients with bladder cancer.

Molecular pathology of urothelial carcinoma

The current personalized oncology era has witnessed significant efforts to integrate clinical, pathological, and molecular classifications. The growing need for molecular biomarkers to feed personalized oncology, together with the unprecedented wealth of knowledge on the molecular basis of bladder cancer, has led to a novel approach to this disease, incorporating molecularly generated data in clinical practice for locally advanced or metastatic disease. Translational research allows a better understanding of the early events in the development of urothelial carcinoma in the urinary bladder. Thus, mutations in the KMT2D and KDM6A chromatin-modifying genes confer competitive advantages that drive cells to colonize larger regions of the urothelium. Additional mutations in TP53, PIK3CA, FGFR3, or RB1 genes then trigger the process of malignant transformation in the urothelium. In the current review, we provide an overview of what could be the expected transition from the morphology-based classification to a combined, molecularly enriched reporting of clinically meaningful parameters aiming to promote personalized oncology of urothelial carcinoma.