Integrated Immunophenotypic Stratification of Urothelial Carcinoma Using CK14, FOXA1, and p16: Correlation With Clinicopathological Features and Patient Outcomes

Abstract

Purpose: Molecular classification of urothelial carcinoma (UC) has important prognostic and therapeutic implications, but routine genomic profiling is not feasible in many settings. Immunohistochemistry (IHC) offers a practical alternative. This study evaluated a CK14-FOXA1-p16 IHC panel for estimating UC molecular subtypes and examined associations between these profiles and clinicopathological features, treatment response, and clinical outcomes. Materials and Methods: We retrospectively analyzed 85 UC cases identified over a 5-year period. Histological features were reviewed according to the 2022 World Health Organization classification. Immunohistochemical staining for CK14, FOXA1, and p16 was evaluated using predefined scoring thresholds. Tumors were classified as basal-like (CK14+/FOXA1-), luminal-like (FOXA1+/CK14-), luminal-unstable (p16 block-type), or indeterminate. Response to intravesical bacillus Calmette-Guérin (BCG) therapy was evaluated only in the non–muscle-invasive bladder cancer (NMIBC) cohort (n=52), whereas disease-free survival (DFS), overall survival, and clinicopathological correlations were analyzed in the full UC cohort (n=85). Associations with clinicopathological factors, recurrence, progression, and survival were assessed using chi-square tests, Kaplan-Meier analysis, and Cox regression. Results: CK14 positivity was observed in 28.2% of tumors and was associated with high-grade disease, muscle invasion, lymphovascular invasion, shorter DFS, and a higher rate of BCG failure. FOXA1 expression (63.5%) was associated with papillary morphology, lower stage, and more favorable outcomes. p16 block-type staining (16.5%) was associated with recurrence risk, particularly in NMIBC. The subtype distribution was 22.4% basal-like, 48.2% luminal-like, 16.5% luminal-unstable, and 12.9% indeterminate. In multivariate analysis, CK14 positivity, FOXA1 loss, and p16 block-type expression were independent predictors of shorter DFS. Conclusion: The CK14-FOXA1-p16 IHC panel provides an affordable approach for estimating UC molecular subtypes and offers useful prognostic stratification. Incorporating this panel into routine pathology workflows may improve risk assessment and support tailored treatment planning, particularly in resource-limited settings.