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Introduction:
Anti-programmed death ligand (PDL1) therapy has shown promising results in tumors with proven PDL 1 expression, including advanced stage urothelial carcinoma of the bladder, however, little is known about PDL1 expression in upper tract urothelial carcinoma (UTUC). We evaluated PDL1 expression in a large series of UTUC.
Materials & Methods:
We studied 99 patients with UTUC. Tissue microarrays TMAs were stained with PD-L1 (Cell-Signaling, E1L3N, 1:100). The degree of tumoral PDL1 was manually scored. PDL1 positivity was defined as >5% tumoral PDL1 staining. The primary outcome of the study was the percentage of tumor cells staining positive for PDL1.
Results:
62% of our cohort had ≥pT2 UTUC. Overall, 45% of tumors were of the renal pelvis, 50% of the ureter, and 4% were of both. The overall rate of PDL1 positivity in our cohort was 15%. For patients with ≥pT2 disease, the rate of PDL1 positivity was 18%. For patients with <pT2 disease, the rate of PDL1 positivity was 11%. Patients with pT4 disease showed the highest rates of PDL1 positivity (4/6, 67%).
Conclusions:
PDL1 positivity was observed in 15% of patients in this cohort of UTUC, with high rates of positivity in advanced stage disease. Anti-PDL1 therapy is an attractive therapeutic target for patients with UTUC, given that neoadjuvant therapy is underutilized and many patients may not be candidates for standard platinum-based therapies in an adjuvant setting. Further studies will be needed to evaluate clinical response rates in UTUC.