Different expression and prognostic implications of PD-L1 in tumor cells and immune cells with the SP263 monoclonal antibody in Chinese urothelial carcinoma patients.

Abstract

e16040 Background: PD-L1 is expressed on tumor cells (TC) and tumor immune cell (IC) infiltrates. The aim of this study was to explore the expression and the clinical implications of PD-L1 in TC and IC with the SP263 monoclonal antibody and the correlation with clinicopathological features and survival prognosis in urothelial carcinoma(UC) patients. Methods: Formalin-fixed paraffin embedded tumor specimens were collected from 172 patients with UC who received nephroureterectomy or cystoscope biopsy in our center from 2009 to 2016. Tumor samples were evaluated for PD-L1 membrane expression by immunohistochemistry (IHC) using VENTANA PD-L1 (SP263) Assay performed on the automated BenchMark ULTRA platform. PD-L1 expression status was determined by PD-L1 membranous staining at any intensity on TC or IC.PD-L1 is defined as positive if either ≥25% TC or ≥25% IC express membranous PD-L1.Data was analyzed by SPSS software. Results: Among 162 patients, TC and IC infiltrate PD-L1 positivity were detected in 16 (9.9%) and 45 cases (27.8%), respectively. The PD-L1 positivity of TC in female (19.4%) was higher than that in male (7.1%), P = 0.029, and so was in the patients with lymph node metastasis (20.7%) than those without metastatic lymph node (7.5%) , P = 0.031.While these correlation were not observed with PD-L1 positivity in IC. PD-L1 positivity both in TC and IC were not related to age, smoking history, specimen type , tumor size , histology grade, pT, pN stage (P > 0.05) .With a median follow-up of 60.9 months, patients with positive PD-L1 expression in IC have more favorable DFS (NR vs 26.3 months, P = 0.032) and OS (NR vs 71.2 months, P = 0.001) than those with negative PD-L1 expression in IC. More significant differences in DFS (NR vs 18 months, P = 0.002) and OS (NR vs 29.8months,P < 0.001) were observed in patients with T2-4 and PD-L1 positive expression. However, We did not find a statistically correlation between PD-L1 positivity in TC and prognostic outcomes. Univariate and multivariate analyses revealed that patients with PD-L1 positive expression in TC had poorer DFS (HR = 2.573; 95% CI, 1.246–5.313;P = 0.011). Whereas positive PD-L1 expression in IC independently correlated with better OS (HR = 0.303; 95% CI, 0.137–0.671;P = 0.003). Conclusions: PD-L1 positivity in IC is higher than TC in urothelial tumor. Positive PD-L1 expression in IC is associated with better OS and DFS while no correlation between PD-L1 positivity in TC and outcome was observed.