Eosinophil granulocytes account for indoleamine 2,3-dioxygenase-mediated immune escape in human non-small cell lung cancer

Simonetta Astigiano, Barbara Morandi, Roberta Costa, Luca Mastracci, Antonella D'Agostino, Giovanni Battista Ratto, Giovanni Melioli, Guido Frumento

Research output: Contribution to journalArticlepeer-review

Abstract

Indoleamine 2,3-dioxygenase (IDO), a catabolizing enzyme of tryptophan, is supposed to play a role in tumor immune escape. Its expression in solid tumors has not yet been well elucidated: IDO can be expressed by the tumor cells themselves, or by ill-defined infiltrating cells, possibly depending on tumor type. We have investigated IDO expression in 25 cases of non-small cell lung cancer (NSCLC). Using histochemistry and immunohistochemistry, we found that IDO was expressed not by tumor cells, but by normal cells infiltrating the peritumoral stroma. These cells were neither macrophages nor dendritic cells, and were identified as eosinophil granulocytes. The amount of IDO-positive eosinophils varied in different cases, ranging from a few cells to more than 50 per field at x200 magnification. IDO protein in NSCLC was enzymatically active. Therefore, at least in NSCLC cases displaying a large amount of these cells in the inflammatory infiltrate, IDO-positive eosinophils could exert an effective immunosuppressive action. On analyzing the 17 patients with adequate follow-up, a significant relationship was found between the amount of IDO-positive infiltrate and overall survival. This finding suggests that the degree of IDO-positive infiltrate could be a prognostic marker in NSCLC.

Original languageEnglish
Pages (from-to)390-396
Number of pages7
JournalNeoplasia (United States)
Volume7
Issue number4
DOIs
Publication statusPublished - Apr 2005

Keywords

  • Eosinophil granulocytes
  • Immune escape
  • Indoleamine 2,3-dioxygenase
  • Non-small cell lung cancer
  • Prognostic marker

ASJC Scopus subject areas

  • Cancer Research

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