PD-L1 Expression in muscle-invasive bladder carcinoma: correlation with tumor–stroma ratio and clinicopathological parameters
Anubhuti Chaturvedi, Irfana Nisam, Varuna Mallya, Shramana Mandal, Chandra Bhushan SinghABSTRACT
Background:
Muscle-invasive bladder carcinoma (MIBC) is an aggressive malignancy with significant morbidity and mortality. The recent incorporation of immune checkpoint inhibitors targeting the PD-1/PD-L1 axis has increased interest in immunohistochemical biomarkers. Tumor–stroma ratio (TSR) has also emerged as a potential prognostic marker reflecting the tumor microenvironment. This study evaluated programmed death-ligand 1 (PD-L1) expression and TSR in MIBC and analyzed their association with clinicopathological parameters.
Materials and Methods:
This retrospective study included 58 cases of biopsy-proven MIBC (pT2 and above) diagnosed over an 8-year period. Histopathological evaluation was performed according to WHO 2022 and AJCC 8
th
edition criteria. PD-L1 immunohistochemistry was carried out using a rabbit monoclonal antibody and interpreted using the combined positive score (CPS), with CPS ≥ 10 considered positive. TSR was assessed histologically using a 50% cutoff. Associations were analyzed using the Chi-square test, with
Results:
The cohort demonstrated a male predominance (86.2%) with a mean age of 58.4 ± 10.2 years. PD-L1 expression was observed in 44.8% of cases and showed a significant association with higher WHO/ISUP tumor grade (
Conclusions:
PD-L1 expression in MIBC correlates with higher tumor grade, whereas tumor–stroma ratio (TSR) is associated with advanced pathological T stage. These findings support the potential role of tumor microenvironment–based markers in pathological stratification of MIBC and warrant further prospective validation.