Daichi Nomoto1, Yoshifumi Baba2, Kazuo Okadome1, Taisuke Yagi1, Rebecca Kalikawe1, Yuki Kiyozumi1, Kazuto Harada1, Kojiro Eto1, Yukiharu Hiyoshi1, Yohei Nagai1, Takatsugu Ishimoto1, Masaaki Iwatsuki1, Shiro Iwagami1, Yuji Miyamoto1, Naoya Yoshida1, Yoshihiro Komohara3, Masayuki Watanabe4, Hideo Baba5. 1. Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. 2. Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan; Department of Next-Generation Surgical Therapy Development, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. 3. Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan. 4. Department of Gastroenterological Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan. 5. Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan; Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto, Japan. Electronic address: hdobaba@kumamoto-u.ac.jp.
Abstract
BACKGROUND: Immune checkpoint inhibitors targeting the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway have demonstrated antitumor effects in patients with various malignancies, including esophageal cancer. Thus, a better understanding of local immunity in esophageal cancer is crucial for improving treatment and clinical outcomes. METHODS: We evaluated PD-1 expression on tumor-infiltrating lymphocytes (TILs), as well as PD-L1 expression on cancer cells, by immunohistochemistry and immunofluorescence using a nonbiased database of 433 curatively resected esophageal cancers. With the idea of application as liquid biopsy, PD-1 expression status on peripheral lymphocytes was evaluated by flow cytometry. RESULTS: The cutoff value of PD-1 expression was the median PD-1 count. Compared with cases of low PD-1 expression (n = 219), cases with high levels of PD-1 expression (n = 213) showed significantly worse overall survival (log-rank P = .0017). The prognostic effect of PD-1 differed according to the preoperative treatment status (P for interaction = .040); PD-1 expression was associated with high overall mortality among patients without preoperative therapy, while no such association was present among those with preoperative treatment. A stratification based on PD-1 and PD-L1 status was also significantly associated with overall survival (log-rank P = .0005). PD-1 expression on TILs was significantly associated with that on peripheral lymphocytes (P < .0001). CONCLUSIONS: PD-1 expression on TILs was associated with an unfavorable clinical outcome in esophageal cancer, supporting its role as a prognostic biomarker. The combination of PD-1 and PD-L1 expression enabled further classification of patients according to clinical outcome.
BACKGROUND: Immune checkpoint inhibitors targeting the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway have demonstrated antitumor effects in patients with various malignancies, including esophageal cancer. Thus, a better understanding of local immunity in esophageal cancer is crucial for improving treatment and clinical outcomes. METHODS: We evaluated PD-1 expression on tumor-infiltrating lymphocytes (TILs), as well as PD-L1 expression on cancer cells, by immunohistochemistry and immunofluorescence using a nonbiased database of 433 curatively resected esophageal cancers. With the idea of application as liquid biopsy, PD-1 expression status on peripheral lymphocytes was evaluated by flow cytometry. RESULTS: The cutoff value of PD-1 expression was the median PD-1 count. Compared with cases of low PD-1 expression (n = 219), cases with high levels of PD-1 expression (n = 213) showed significantly worse overall survival (log-rank P = .0017). The prognostic effect of PD-1 differed according to the preoperative treatment status (P for interaction = .040); PD-1 expression was associated with high overall mortality among patients without preoperative therapy, while no such association was present among those with preoperative treatment. A stratification based on PD-1 and PD-L1 status was also significantly associated with overall survival (log-rank P = .0005). PD-1 expression on TILs was significantly associated with that on peripheral lymphocytes (P < .0001). CONCLUSIONS: PD-1 expression on TILs was associated with an unfavorable clinical outcome in esophageal cancer, supporting its role as a prognostic biomarker. The combination of PD-1 and PD-L1 expression enabled further classification of patients according to clinical outcome.