%0 Journal Article
%T Immune checkpoint blockade in esophageal squamous cell carcinoma: is it ready for prime time?
%A Eirini Pectasides
%J SCIE-indexed Journal
%D 2018
%R 10.21037/jtd.2018.02.74
%X Esophageal cancer is a lethal disease with limited treatment options, particularly in the metastatic setting. While the incidence of esophageal squamous cell carcinoma (ESCC) has declined worldwide, it remains a major cause of morbidity and mortality in Asia, Africa and South America (1). In contrast to esophageal adenocarcinoma, which develops in the lower esophagus and is related to gastric reflux and BarrettĄ¯s esophagus, ESCC occurs in the upper/mid esophagus and is associated with tobacco and alcohol use (2). Despite their differences, a common feature of both ESCC and adenocarcinoma is the presence of chronic inflammation and an abundance of tumor-infiltrating lymphocytes and other immune cell populations. As shown in other malignancies, infiltration of the tumor by CD8+ T cells was associated with improved outcomes (3,4), while the presence of regulatory T cells and myeloid-derived suppressor cells was correlated with worse overall survival (5,6). Furthermore, a small number of studies have evaluated the role of immune inhibitory signals, specifically the programmed cell death-1 (PD-1) protein and its ligands PD-L1 and PD-L2, in ESCC. One such study used gene expression to investigate the clinical significance of PD-L1 and PD-L2 in 41 cases of ESCC. In this series, 43.9% of patients had PD-L1 or PD-L2-positive tumors, determined by real-time quantitative PCR. PD-L1 and PD-L2 positivity was found to be a poor prognostic factor, in both univariate and multivariate analysis (7). A more recent study confirmed these findings. Of 106 patients with ESCC who underwent surgery without prior chemotherapy or radiation, 63 (59.4%) had tumors positive for either or both PD-L1 and PD-L2. PD-L1 and PD-L2 positivity predicted for worse overall survival (8). Furthermore, PD-L1 positivity has been associated with advanced stage, nodal metastasis, poor response to neoadjuvant chemoradiotherapy and locoregional recurrence (9)
%U http://jtd.amegroups.com/article/view/19645/html