Tissue microarrays from 251 MIBC patients analyzed for RB1, p53, and p21 expression.

Evaluation of 4518 tissue cores, including three cores each from tumor center and tumor front per patient.

High concordance of marker expression between tumor center and front, minimizing the impact of sampling location on diagnostic accuracy.

RB1, p53, and p21 alone are insufficient as prognostic indicators.

Combined loss of two or three markers strongly correlates with reduced overall and cancer-specific survival.

Muscle-invasive bladder cancer (MIBC) represents a genetically heterogeneous disease with limited prognostic markers. This study aimed to validate the prognostic relevance of combined alterations in cell cycle regulators RB1, p53, and p21 in a broad cohort of MIBC patients undergoing radical cystectomy (RC).

We analyzed formalin-fixed paraffin-embedded material from MIBC patients who underwent RC at the Department of Urology, University Hospital, Ludwig-Maximilians-University Munich. Tissue microarrays (TMAs) from 251 MIBC patients (pT2-pT4) were constructed, incorporating triplicate cores from tumor center and front. Immunohistochemical expression of RB1, p53, and p21 was assessed using a four-grade scoring system. Prognostic associations with overall survival (OS) and cancer-specific survival (CSS) were evaluated using multivariable Cox regression, Kaplan-Meier curves, and log-rank tests.

We assessed 4518 stainings from 251 patients. Single marker analysis revealed no significant association between the loss of RB1, p53, or p21 and OS or CSS. However, the loss of two or three markers was significantly associated with worse OS (HR 3.49, 95 % CI 1.28–9.50; p = 0.01) and CSS (HR 11.2, 95 % CI 1.46–86.04; p = 0.02).

RB1, p53, and p21 are insufficient as single prognostic markers in MIBC but demonstrate significant prognostic relevance when analyzed in combination. These findings underscore the need for multi-marker approaches in prognostic modeling and personalized treatment strategies for MIBC.

Urothelial carcinoma

Muscle-invasive bladder cancer

MIBC

RB1

P53

P21

Prognostic markers

© 2025 The Authors. Published by Elsevier GmbH.