[1] Enzinger PC, Mayer RJ. Esophageal cancer. N Engl J Med. 2003;349:2241-52.
[2] Kato H, Fukuchi M, Miyazaki T, et al. Surgical treatment for esophageal cancer. Current issues. Dig Surg. 2007;24:88-95.
[3] Jung KW, Won YJ, Oh CM, et al. Prediction of Cancer Incidence and Mortality in Korea, 2017. Cancer Res Treat. 2017;49:306-12.
[4] Kelly RJ. The emerging role of immunotherapy for esophageal cancer. Curr Opin Gastroenterol. 2019.
[5] Rong L, Wang B, Guo L, et al. HER2 expression and relevant clinicopathological features in esophageal squamous cell carcinoma in a Chinese population. Diagn Pathol. 2020;15:27.
[6] Doi T, Piha-Paul SA, Jalal SI, et al. Safety and Antitumor Activity of the Anti-Programmed Death-1 Antibody Pembrolizumab in Patients With Advanced Esophageal Carcinoma. J Clin Oncol. 2018;36:61-7.
[7] Chen J, Jiang CC, Jin L, et al. Regulation of PD-L1: a novel role of pro-survival signalling in cancer. Ann Oncol. 2016;27:409-16.
[8] Integrated genomic characterization of oesophageal carcinoma. Nature. 2017;541:169-75.
[9] Black M, Barsoum IB, Truesdell P, et al. Activation of the PD-1/PD-L1 immune checkpoint confers tumor cell chemoresistance associated with increased metastasis. Oncotarget. 2016;7:10557-67.
[10] Chen N, Fang W, Zhan J, et al. Upregulation of PD-L1 by EGFR Activation Mediates the Immune Escape in EGFR-Driven NSCLC: Implication for Optional Immune Targeted Therapy for NSCLC Patients with EGFR Mutation. J Thorac Oncol. 2015;10:910-23.
[11] Kwon MJ, Rho YS, Nam ES, et al. Clinical implication of programmed cell death-1 ligand-1 expression in tonsillar squamous cell carcinoma in association with intratumoral heterogeneity, human papillomavirus, and epithelial-to-mesenchymal transition. Hum Pathol. 2018;80:28-39.
[12] Kwon MJ, Kim KC, Nam ES, et al. Programmed death ligand-1 and MET co-expression is a poor prognostic factor in gastric cancers after resection. Oncotarget. 2017;8:82399-414.
[13] Le DT, Durham JN, Smith KN, et al. Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade. Science. 2017;357:409-13.
[14] Amin MB, American Joint Committee on Cancer., American Cancer Society. AJCC cancer staging manual. 8th ed. Chicago IL: American Joint Committee on Cancer, Springer; 2017. p. xvii, 1024 pages.
[15] Brown IS, Fujii S, Kawachi H, et al. Tumours of the oesophagus. In: R.D. O, Lam AK, Ochiai A, et al., editors. WHO Classification of Tumours Digestive System Tumours. 5th ed. Lyon, France: International Agency for Research on Cancer; 2019. p. 23-58.
[16] Kim R, Keam B, Kwon D, et al. Programmed death ligand-1 expression and its prognostic role in esophageal squamous cell carcinoma. World J Gastroenterol. 2016;22:8389-97.
[17] Hayashi M, Tamura G, Jin Z, et al. Microsatellite instability in esophageal squamous cell carcinoma is not associated with hMLH1 promoter hypermethylation. Pathol Int. 2003;53:270-6.
[18] Taieb J, Shi Q, Pederson L, et al. Prognosis of microsatellite instability and/or mismatch repair deficiency stage III colon cancer patients after disease recurrence following adjuvant treatment: results of an ACCENT pooled analysis of seven studies. Ann Oncol. 2019;30:1466-71.
[19] Lim SH, Hong M, Ahn S, et al. Changes in tumour expression of programmed death-ligand 1 after neoadjuvant concurrent chemoradiotherapy in patients with squamous oesophageal cancer. Eur J Cancer. 2016;52:1-9.
[20] Ito S, Okano S, Morita M, et al. Expression of PD-L1 and HLA Class I in Esophageal Squamous Cell Carcinoma: Prognostic Factors for Patient Outcome. Ann Surg Oncol. 2016;23:508-15.
[21] Tanaka K, Miyata H, Sugimura K, et al. Negative influence of programmed death-1-ligands on the survival of esophageal cancer patients treated with chemotherapy. Cancer Sci. 2016;107:726-33.
[22] Hatogai K, Kitano S, Fujii S, et al. Comprehensive immunohistochemical analysis of tumor microenvironment immune status in esophageal squamous cell carcinoma. Oncotarget. 2016;7:47252-64.
[23] Jesinghaus M, Steiger K, Slotta-Huspenina J, et al. Increased intraepithelial CD3+ T-lymphocytes and high PD-L1 expression on tumor cells are associated with a favorable prognosis in esophageal squamous cell carcinoma and allow prognostic immunogenic subgrouping. Oncotarget. 2017;8:46756-68.
[24] Chen K, Cheng G, Zhang F, et al. Prognostic significance of programmed death-1 and programmed death-ligand 1 expression in patients with esophageal squamous cell carcinoma. Oncotarget. 2016;7:30772-80.
[25] Jiang Y, Lo AWI, Wong A, et al. Prognostic significance of tumor-infiltrating immune cells and PD-L1 expression in esophageal squamous cell carcinoma. Oncotarget. 2017;8:30175-89.
[26] Balar AV, Galsky MD, Rosenberg JE, et al. Atezolizumab as first-line treatment in cisplatin-ineligible patients with locally advanced and metastatic urothelial carcinoma: a single-arm, multicentre, phase 2 trial. Lancet. 2017;389:67-76.
[27] Wakita A, Motoyama S, Nanjo H, et al. PD-L1 Expression Is a Prognostic Factor in Patients with Thoracic Esophageal Cancer Treated Without Adjuvant Chemotherapy. Anticancer Res. 2017;37:1433-41.
[28] Ng HY, Li J, Tao L, et al. Chemotherapeutic Treatments Increase PD-L1 Expression in Esophageal Squamous Cell Carcinoma through EGFR/ERK Activation. Transl Oncol. 2018;11:1323-33.
[29] Twyman-Saint Victor C, Rech AJ, Maity A, et al. Radiation and dual checkpoint blockade activate non-redundant immune mechanisms in cancer. Nature. 2015;520:373-7.
[30] Maeng CH, Lee J, van Hummelen P, et al. High-throughput genotyping in metastatic esophageal squamous cell carcinoma identifies phosphoinositide-3-kinase and BRAF mutations. PLoS One. 2012;7:e41655.
[31] Shigaki H, Baba Y, Watanabe M, et al. PIK3CA mutation is associated with a favorable prognosis among patients with curatively resected esophageal squamous cell carcinoma. Clin Cancer Res. 2013;19:2451-9.
[32] Mori R, Ishiguro H, Kimura M, et al. PIK3CA mutation status in Japanese esophageal squamous cell carcinoma. J Surg Res. 2008;145:320-6.
[33] Kim HS, Lee SE, Bae YS, et al. PIK3CA amplification is associated with poor prognosis among patients with curatively resected esophageal squamous cell carcinoma. Oncotarget. 2016;7:30691-701.
[34] Shigaki H, Baba Y, Watanabe M, et al. KRAS and BRAF mutations in 203 esophageal squamous cell carcinomas: pyrosequencing technology and literature review. Ann Surg Oncol. 2013;20 Suppl 3:S485-91.
[35] Matsumoto Y, Nagasaka T, Kambara T, et al. Microsatellite instability and clinicopathological features in esophageal squamous cell cancer. Oncol Rep. 2007;18:1123-7.
[36] Kagawa Y, Yoshida K, Hirai T, et al. Microsatellite instability in squamous cell carcinomas and dysplasias of the esophagus. Anticancer Res. 2000;20:213-7.
[37] Ludmir EB, Stephens SJ, Palta M, et al. Human papillomavirus tumor infection in esophageal squamous cell carcinoma. J Gastrointest Oncol. 2015;6:287-95.