Abstract 4692: High density of cytotoxic and regulatory T-lymphocytes in gastric cancers with microsatellite instability

• Published in: Cancer research (Chicago, Ill.) Ill.), 2018-07, Vol.78 (13_Supplement), p.4692-4692
• Main Authors: Kim, Hyoung-Il, Shin, Su-Jin, Kim, Sang Yong, Choi, Yoon Young, Son, Taeil, Cheong, Jae-Ho, Hyung, Woo Jin, Noh, Sung Hoon
• Format: Article
• Language: English
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM2018-4692

Introduction: MSI-high (MSI-H) colorectal cancer is known to be associated with increased tumor-infiltrating lymphocytes (TILs) and good prognosis. In gastric cancer, however, MSI status has rarely been evaluated in accordance with TILs. The objectives of our study were to clarify the relationships between MSI status and antitumor host immune response and to identify the impact of these factors on the prognosis of gastric cancer. Methods: We evaluated 345 patients with gastric cancer who underwent gastrectomy with MSI typing. The numbers of TILs in tumor center was counted after immunohistochemical staining with anti-CD3, CD4, CD8, Foxp3, and granzyme B to quantify the subset of TILs. To evaluate systemic immune response, differential white blood cell count and prognostic nutritional index (PNI) were obtained. Results: Of the 345 patients, 57 were MSI-H and 288 were non-MSI-H groups. MSI-H tumors carried significantly higher numbers of CD8+ T-cells, Foxp3+ T-cells, GZB+ T cells and higher ratio of Foxp3/CD4 and GZB/CD8. The prognostic effect of TILs was different in MSI-H and non-MSI-H groups. All subsets of TILs were not significant prognostic factor for recurrent-free survival (RFS) and overall survival (OS) in MSI-H group. However, in non-MSI-H group, multivariate analysis showed that stage, PNI and CD4+ T cells was independent prognostic factor for RFS; on the other hand, stage, PNI and ratio of Foxp3/CD4 was independent prognostic factor for OS. Conclusions: The number of subset of TILs and the prognostic influence of systemic and local immune response were different between MSI-H and non-MSI-H tumors. The immunogenicity caused by microsatellite instability and subsequent host immune response is associated with cancer progression and patient prognosis of gastric cancer. Citation Format: Hyoung-Il Kim, Su-Jin Shin, Sang Yong Kim, Yoon Young Choi, Taeil Son, Jae-Ho Cheong, Woo Jin Hyung, Sung Hoon Noh. High density of cytotoxic and regulatory T-lymphocytes in gastric cancers with microsatellite instability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4692.