PD-L1 hotspot in tumor-infiltrating lymphocytes of radically treated esophageal squamous cell carcinoma: Pattern of recurrence and long-term clinical outcomes

Abstract

Introduction: Most cases of esophageal squamous cell carcinoma (ESCC) recurred and eventually succumbed to the disease despite radical treatment. Immune checkpoint inhibitor showed early promise in metastatic disease and preliminary evidence has suggested PD-L1 staining on tumor cells as a predictive marker for treatment outcomes. On the other hand, the role of PD-L1 on tumor-infiltrating lymphocytes (TILs) has not been fully elucidated. We retrospectively analysed PD-L1 immunohistochemical (IHC) staining on both tumor cells and TILs.