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Relationship between Fas‐ligand expression on carcinoma cell and cytotoxic T‐lymphocyte response in lymphoepithelioma‐like cancer of the stomach
Author(s) -
Kume Tohru,
Oshima Koichi,
Yamashita Yuichi,
Shirakusa Takayuki,
Kikuchi Masahiro
Publication year - 1999
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19990820)84:4<339::aid-ijc1>3.0.co;2-2
Subject(s) - fas ligand , cytotoxic t cell , cd8 , immune system , apoptosis , ctl* , biology , tumor infiltrating lymphocytes , fas receptor , lymphocyte , cancer research , immunology , microbiology and biotechnology , programmed cell death , in vitro , biochemistry
The Fas/Fas‐ligand (Fas‐L) system is involved in the induction of apoptosis and mediates T‐cell cytotoxicity. We investigated the Fas/Fas‐L system and cytotoxic T lymphocytes (CTLs) in 30 lymphoepithelioma‐like cancer of the stomach (LECS) in order to understand the immune evasion of the tumor cells. Epstein‐Barr virus (EBV) was detected in 15 cases in 30 LECSs. The expressions of Fas and Fas‐L in tumor cells, and TIA‐1, CD4, CD8 and CD56 in lymphocytes were examined by immunohistochemical staining. Apoptosis of tumor cells and lymphocytes was detected by the terminal deoxynucleotidyl‐mediated dUTP‐nick end labeling method (TUNEL). Expression of Fas and Fas‐L was detected in tumor cells in 10 and 17 LECS, respectively. CTL consisted predominantly of CD8 (CD8 + > CD4 + ), whereas natural killer (NK) cells were detected in 4 cases only. In Fas‐L‐positive tumors, the TIA‐1‐positive lymphocyte count was significantly lower ( p < 0.05) and the number of apoptotic lymphocytes was significantly higher ( p < 0.05) than in Fas‐L‐negative cases. The number of TIA‐1‐positive lymphocytes in EBV + cases was significantly higher than that in the EBV − tumors ( p < 0.05). The number of apoptotic tumor cells in EBV + tumors was significantly lower than in EBV − cases ( p < 0.01). Our results suggest that in LECS, tumor cells expressing Fas‐L may evade the immune attack by killing lymphocytes through the Fas/Fas‐L system. However, in EBV + LECS tumors, our results indicate that a high number of CTL is associated with a reduction in the number of apoptotic tumor cells. Our findings indicate that the Fas/Fas‐L system plays a role in immune evasion of tumor cells in EBV + tumors. Int. J. Cancer (Pred. Oncol.) 84:339–343, 1999. © 1999 Wiley‐Liss, Inc.