Objective: To analyze the relationship between the expression of programmed-death ligand1 (PD-L1) and the clinicopathological features and prognosis of upper tract urothelial carcinoma (UTUC).Postoperative follow-up was performed to evaluate the prognosis of the patients, and to analyze the correlation between the expression of PD-L1 and the prognosis of the patients. Methods: Immunohistochemistry (IHC) was used to detect the expression of PD-L1 in 151 patients with UTUC radical nephroureterectomy (RNU). Results:The median age of the patients was 52 years old (range: 36-74 years old). The median follow-up time was 63months (range: 1-100 months), and the expression of PD-L1 was negative in 50 (33%) of the samples. Negative PD-L1 expression was significantly associated with higher tumor pathologic stage (P=0.04), higher lesion grade(P=0.01), and lymphovascular invasion (P<0.01). Kaplan-Meier survival curve analysis showed that PD-L1 negative expression was associated with poor tumor-free survival (P=0.01) and poor cancer-specific survival(P=0.01). Multivariate Cox regression analysis showed that negative PD-L1 expression was significant associated with disease recurrence (HR=2.05, 95%CI=1.06-3.96, P=0.032) and cancer-specific mortality (HR=2.89, 95%CI=
1.22-6.82, P=0.024), after adjusting for tumor pathological stage, lesion grade, lymph node metastasis, and lymphovascular invasion. Conclusion: Negative PD-L1 expression is an independent predictor of cancer recurrence and tumor-specific survival after UTUC radical nephroureterectomy, indicating the necessity of
incorporating UTUC patients into immunotherapy clinical trials.