PT  - JOURNAL ARTICLE
AU  - Zaibo Li
AU  - Amy S. Joehlin-Price
AU  - Jennifer Rhoades
AU  - Martins Ayoola-Adeola
AU  - Karin Miller
AU  - Anil V. Parwani
AU  - Floor J. Backes
AU  - Ashley S. Felix
AU  - Adrian A. Suarez
TI  - Programmed Death Ligand 1 Expression Among 700 Consecutive Endometrial Cancers: Strong Association With Mismatch Repair Protein Deficiency
AID  - 10.1097/IGC.0000000000001120
DP  - 2018 Jan 01
TA  - International Journal of Gynecologic Cancer
PG  - 59--68
VI  - 28
IP  - 1
4099  - http://ijgc.bmj.com/content/28/1/59.short
4100  - http://ijgc.bmj.com/content/28/1/59.full
SO  - Int J Gynecol Cancer2018 Jan 01; 28
AB  - Objective This study aims to determine the prevalence of programmed death ligand 1 (PD-L1) expression in endometrial carcinoma (EC) and determine clinical and pathological associations.Methods Immunohistochemistry for PD-L1 was performed on sections of a triple-core tissue microarray of 700 ECs. Positive PD-L1 expression, defined as 1% of cells staining positive, was evaluated in tumor and stromal compartments. Using age-adjusted logistic regression, we estimated odds ratios and 95% confidence intervals for associations between PD-L1 expression (overall and by staining compartment) with clinical and tumor characteristics. Kaplan-Meier plots and log-rank tests were used to evaluate associations between PD-L1 expression and EC-specific survival.Results PD-L1 expression was observed in 100 cases (14.3%), including 27 (3.9%) with expression in tumor cells only, 35 (5.0%) with expression in both tumor cells and stroma, and 38 (5.4%) with expression in stroma only. Expression was observed in ECs of different histologic types. Tumors characterized by loss of mismatch repair proteins were significantly associated with tumoral PD-L1 expression (P < 0.0001), but not with stromal PD-L1 expression. Both tumoral and stromal PD-L1 expressions were associated with high-grade endometrioid histology, nonendometrioid histology, and lymphovascular space invasion. We observed no significant associations between PD-L1 expression and EC-specific survival.Conclusions PD-L1 is expressed in a significant proportion of EC and is associated with mismatch repair deficiency, potentially representing a mechanism of tumor immune evasion and a therapeutic target in EC.