Association of PD-L1 and PD-1 Expression With Clinicopathological Characteristics and Prognosis in Upper Tract...

To investigate the expression of PD-L1/PD-1 in tumor cells and tumor-infiltrating immune cells (TIICs) and their association with clinicopathologic characteristics and prognosis in UTUC.

Immunohistochemistry (IHC) was performed to detect the expression of PD-L1 and PD-1 in 124 formalin-fixed paraffin embedded tumor specimens in UTUC. Clinicopathological variables and overall survival (OS) were documented. Association between PD-L1, PD1 with clinicopathologic characteristics and OS were evaluated using binary logistic regression or Cox regression. Statistical significance was considered at 0.05.

Of 113 eligible patients (11 excluded due to insufficient tissue), 31.9% (36/113) showed PD-L1⁺ tumor cells, and 28.8% (29/101) had PD-L1⁺ TIICs. PD-1⁺ TIICs were observed in 58.4% (59/101). PD-L1 expression in tumor cells correlated significantly with high tumor grade (P = .029). PD-L1⁺ tumor cells predicted reduced OS in univariate (HR = 1.83, P = .025) and multivariable analyses (HR = 2.15, P = .007). PD-1⁺ TIICs associated with early-stage disease (P = .005) but not OS (P = .166). PD-L1⁺ TIICs also showed no OS association (P = .644).

PD-L1 is expressed in 31.9% of UTUC tumors and 28.8% of TIICs, while PD-1 is detected in 58.4% of TIICs. Tumor cell PD-L1 positivity independently predicts poor survival and may drive UTUC progression. PD-1⁺ TIICs correlate with early-stage disease but lack prognostic value for OS. These findings highlight PD-L1 as a potential biomarker for risk stratification in UTUC.