title: CCL17 and CCL22 chemokines within tumor microenvironment are related to accumulation of Foxp3+ regulatory T cells in gastric cancer.
abstract: It has been reported that an increased population of regulatory T cells (Tregs) is one of the reasons for impaired anti-tumor immunity. Recently, Foxp3 has been reported as a reliable marker of Tregs. The authors investigated the frequency of Foxp3(+) Tregs within CD4(+) cells in TILs, regional lymph nodes and PBLs of gastric cancer patients (n = 45). Furthermore, to elucidate the mechanisms behind Treg accumulation within tumors, they evaluated the relationship between CCL17 or CCL22 expression and the frequency of Foxp3(+) Tregs in gastric cancer. CD4(+)CD25(+)Foxp3(+) Tregs as a percentage of CD4(+) cells were counted by flow cytometry and evaluated by immunohistochemistry. Moreover, an in vitro migration assay using Tregs derived from gastric cancers was performed in the presence of CCL17 or CCL22. As a result, the frequency of Foxp3(+) Tregs in TILs was significantly higher than that in normal gastric mucosa (12.4% +/- 7.5% vs. 4.1% +/- 5.3%, p < 0.01). Importantly, the increase in Tregs in TILs occurred to the same extent in early and advanced disease. Furthermore, the frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells within tumors was significantly higher than that of normal gastric mucosa, and there was a significant correlation between the frequency of CCL17(+) or CCL22(+) cells and Foxp3(+) Tregs in TILs. In addition, the in vitro migration assay indicated that Tregs were significantly induced to migrate by CCL17 or CCL22. In conclusion, CCL17 and CCL22 within the tumor are related to the increased population of Foxp3(+) Tregs, with such an observation occurring in early gastric cancer.
authors.affiliation: First Department of Surgery, University of Yamanashi, 1110 Shimokato, Chuo-city, Yamanashi, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Mizukami
authors.forename: Koji
authors.initials: K
authors.lastname: Kono
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Hidenori
authors.initials: H
authors.lastname: Akaike
authors.forename: Kazuyasu
authors.initials: K
authors.lastname: Kamimura
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Sugai
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujii
mesh_terms: D000368:Aged; D018106:CD28 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002465:Cell Movement; D054414:Chemokine CCL17 / Q000378:metabolism*; D054422:Chemokine CCL22 / Q000378:metabolism*; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D005753:Gastric Mucosa / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D008198:Lymph Nodes / Q000473:pathology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology / Q000473:pathology; D008297:Male; D013274:Stomach Neoplasms / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology
chemical_list: C106230:CCL17 protein, human; C515482:CCL22 protein, human; D018106:CD28 Antigens; D054414:Chemokine CCL17; D054422:Chemokine CCL22; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors