title: Resistance to apoptosis and expansion of regulatory T cells in relation to the detection of circulating tumor cells in patients with metastatic epithelial cancer.
abstract: Regulatory T cells may be crucial in the development of T cell tolerance to malignancies and contribute to immune dysfunctions. We investigated the percentage, activity, and onset of apoptosis of T cell subpopulations by multicolor flow cytometry in metastatic epithelial cancer patients compared to normal controls. Furthermore, a possible relationship between the presence of circulating tumor cells detected by immunocytochemistry and immune cell abnormalities was evaluated. Our study demonstrated a significantly elevated proportion of regulatory T cells in cancer patients (p < 0.001). In contrast to all other T cell subpopulations, regulatory T cells showed comparable Annexin V-binding characteristics in patients and normal controls. No relationship between the detection of circulating tumor cells and immune dysfunction was observed. These results indicate that cancer patients have a higher number of regulatory T cells with resistance to apoptotic stimuli partly responsible for immune dysfunctions as often observed in cancer patients.
authors.affiliation: Division of Oncology, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria. stefanie.stanzer@meduni-graz.at
authors.forename: Stefanie
authors.initials: S
authors.lastname: Stanzer
authors.forename: Nadia
authors.initials: N
authors.lastname: Dandachi
authors.forename: Marija
authors.initials: M
authors.lastname: Balic
authors.forename: Margit
authors.initials: M
authors.lastname: Resel
authors.forename: Hellmut
authors.initials: H
authors.lastname: Samonigg
authors.forename: Thomas
authors.initials: T
authors.lastname: Bauernhofer
mesh_terms: D000368:Aged; D017304:Annexin A5 / Q000737:chemistry; D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D060908:CTLA-4 Antigen; D002277:Carcinoma / Q000097:blood* / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
chemical_list: D017304:Annexin A5; D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D019014:fas Receptor