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World J Gastrointest Oncol. Jul 15, 2017; 9(7): 293-299
Published online Jul 15, 2017. doi: 10.4251/wjgo.v9.i7.293
Clinical significance of tumor-infiltrating lymphocytes for gastric cancer in the era of immunology
Byung Woog Kang, Jong Gwang Kim, In Hee Lee, Han Ik Bae, An Na Seo
Byung Woog Kang, Jong Gwang Kim, In Hee Lee, Department of Hematology/Oncology, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu 41404, South Korea
Han Ik Bae, An Na Seo, Department of Pathology, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu 41404, South Korea
Author contributions: Kang BW and Kim JG performed the majority of the study, wrote the manuscript; Lee IH, Bae HI and Seo AN conceived the study and finalized the revision; all authors read and approved the final manuscript.
Conflict-of-interest statement: There is no conflict of interest in this manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Jong Gwang Kim, MD, PhD, Department of Hematology/Oncology, Kyungpook National University Hospital, Kyungpook National University School of Medicine, 807 Hogukno, Buk-gu, Daegu 41404, South Korea. jkk21c@knu.ac.kr
Telephone: +82-53-2003521 Fax: +82-53-2002029
Received: October 20, 2016
Peer-review started: October 23, 2016
First decision: December 20, 2016
Revised: February 2, 2017
Accepted: June 6, 2017
Article in press: June 8, 2017
Published online: July 15, 2017
Abstract

Immunotherapy has begun to revolutionize cancer treatment, by introducing therapies that target the host immune system instead of the tumor, therapies that possess unique adverse event profiles, and therapies that may cure certain types of cancer. The immune microenvironment of tumors is emerging as the most important means of understanding the relationship between a patient’ immune system and their cancer, informing prognosis, and guiding immunotherapy, such as an antibody blockade of immune checkpoints. For some solid tumors, simple quantitation of lymphocyte infiltration would seem to have prognostic significance, suggesting that lymphocyte infiltration is not passive but may actively promote or inhibit tumor growth. For gastric cancers, several studies have provided strong evidence that immune cells contribute to determining prognosis. However, the exact role of immune cells in gastric cancer remains unclear. Therefore, this review focuses on the clinical significance of immune cells, especially tumor-infiltrating lymphocytes, in gastric cancer.

Keywords: Gastric cancer, Tumor-infiltrating lymphocytes, Immunotherapy

Core tip: Tumor-infiltrating lymphocytes (TILs) are considered a manifestation of the host immune response against tumor cells, and several studies have already reported the potential of TILs as a prognostic parameter for various human malignancies. However, only a few studies have investigated the prognostic impact of TILs in gastric cancer. Based on a comprehensive molecular characterization of gastric cancer, TILs could be a potential biomarker. Accordingly, this review focuses on the clinical significance of immune cells, especially TILs, in gastric cancer.