Molecular Pathologic Subtyping of Urothelial Bladder Carcinoma in Young Patients

The Role of Immunohistochemistry as a Surrogate Marker in Molecular Subtyping and Classification of Bladder Cancer

BACKGROUND/OBJECTIVES

Bladder cancer (BC) is a highly heterogeneous disease, presenting clinical challenges, particularly in predicting patient outcomes and selecting effective treatments. Molecular subtyping has emerged as an essential tool for understanding the biological diversity of BC; however, its implementation in clinical practice remains limited due to the high costs and complexity of genomic techniques. This review examines the role of immunohistochemistry (IHC) as a surrogate marker for molecular subtyping in BC, highlighting its potential to bridge the gap between advanced molecular classifications and routine clinical application; Methods: We explore the evolution of taxonomic classification in BC, with a particular focus on cytokeratin (KRT) expression patterns in normal urothelium, which are key to identifying basal and luminal subtypes. Furthermore, we emphasise the need for consensus on IHC markers to reliably define these subtypes, facilitating wider and standardised clinical use. The review also analyses the application of IHC in both muscle-invasive (MIBC) and non-muscle-invasive bladder cancer (NMIBC), with particular attention to the less extensively studied NMIBC cases. We discuss the practical advantages of IHC for subtyping, including its cost effectiveness and feasibility in standard pathology laboratories, alongside ongoing challenges such as the requirement for standardised protocols and external validation across diverse clinical settings; Conclusions: While IHC has limitations, it offers a viable alternative for laboratories lacking access to advanced molecular techniques. Further research is required to determine the optimal combination of markers, establish a consensus diagnostic algorithm, and validate IHC through large-scale trials. This will ultimately enhance diagnostic accuracy, guide treatment decisions, and improve patient outcomes.

Risk of bladder cancer death in patients younger than 50 with non-muscle-invasive and muscle-invasive bladder cancer

INTRODUCTION AND OBJECTIVES

Bladder cancer is primarily a disease of older age and little is known about the differences between patients diagnosed with bladder cancer at a younger versus older age. Our objectives were to compare bladder cancer specific survival in patients aged <50 versus those aged 50-70 at time of diagnosis.

MATERIALS AND METHODS

The Swedish bladder cancer database provided data on patient demographics, clinical characteristics and treatments for this observational study. Cox proportional hazard regression models were adjusted for appropriate variables. All analyses were stratified by disease stage (non-muscle-invasive bladder cancer and muscle-invasive bladder cancer. Furthermore, we compared the frequency of lower urinary tract infections within 24 months prior to bladder cancer diagnosis by sex and age groups.

RESULTS

The study included 15,452 newly-diagnosed BC patients (1997-2014); 1,207 (8%) patients were <50 whilst 14,245 (92%) were aged 50-70. Patients aged <50 at diagnosis were at a decreased risk of bladder cancer death (HR = 0.82, 95%CI: 0.68-0.99) compared to those aged 50-70. When stratified by non-muscle-invasive and muscle-invasive bladder cancer, this association remained in non-muscle-invasive patients only (<50, HR = 0.43, 95% CI: 0.28-0.64). The frequency of lower urinary tract infection diagnoses did not differ between younger and older patients in either men or women.

CONCLUSIONS

Patients diagnosed with non-muscle-invasive bladder cancer when aged <50 are at decreased risk of bladder cancer-specific death when compared to their older (50-70) counterparts. These observations raise relevant research questions about age-related differences in diagnostic procedures, clinical decision-making and, not least, potential differences in tumour biology.

Primary Urothelial Bladder Cancer in a Young Patient: A Case Report and Review of the Literature

Despite being a rare condition among young patients, here, we report about a 22-year-old patient with primary urothelial bladder cancer. The patient complained of macroscopic painless hematuria. Transabdominal ultrasound revealed a 2-cm-sized exophytic lesion occupying the left-sided urinary bladder wall. The histologic examination of a specimen obtained during transurethral resection of the bladder tumor showed a superficial low-grade urothelial bladder tumor, pTa G1. Close follow-up with regular cystoscopies and urine cytological examinations is the cornerstone in the disease’s therapy. Underlying genetic factors may predispose to the development of the disease, which may require further investigations.

The value and limitations of urothelial bladder carcinoma molecular classifications to predict oncological outcomes and cancer treatment response: A systematic review and meta-analysis

AIM

To evaluate the predictive value of molecular subtypes on oncological outcomes and response to cancer treatment in patients with urothelial bladder carcinoma (UBC).

MATERIALS AND METHODS

A literature search using PubMed, Scopus, and Cochrane Library was conducted on April 2020 to identify relevant studies according to the preferred reporting items for systematic review and meta-analysis guidelines. The pooled overall survival (OS), cancer-specific survival (CSS), and progression-free survival were calculated using a fixed or random effects model.

RESULTS

We identified 66 studies (including 21,447 molecular subtype records) evaluating the impact of molecular classification on oncologic outcomes in patients with UBC. We found significant association of different molecular subtypes with OS, CSS, progression-free survival, recurrence-free survival, and response to treatment. Totally, 11 studies were included in the meta-analysis. Basal group and NE-like subtypes were associated with worse OS (pooled HR: 1.78, 95%CI: 1.49-2.12, and pooled HR: 2.67, 95%CI: 1.08-6.60, respectively) in patients with muscle invasive bladder cancer. Luminal group was also associated with worse CSS (pooled HR of 3.67, 95%CI: 2.19-6.14).

CONCLUSIONS

Based on these data, UBC molecular classifications are significant predictors of oncological outcomes and identify patients who are most likely to benefit from intensified or different therapies. The optimal consensus on molecular classification remains to be verified in well-designed prospective studies to allow precise prognostic and predictive value assessment.