title: Circulating myeloid-derived suppressor cells in patients with pancreatic cancer.
abstract: BACKGROUND
  Myeloid-derived suppressor cells (MDSCs) are heterogeneous cell types that suppress T-cell responses in cancer patients and animal models, some MDSC subpopulations are increased in patients with pancreatic cancer. The present study was to investigate a specific subset of MDSCs in patients with pancreatic cancer and the mechanism of MDSCs increase in these patients.
  
  
  METHODS
  Myeloid cells from whole blood were collected from 37 patients with pancreatic cancer, 17 with cholangiocarcinoma, and 47 healthy controls. Four pancreatic cancer cell lines were co-cultured with normal peripheral blood mononuclear cells (PBMCs) to test the effect of tumor cells on the conversion of PBMCs to MDSCs. Levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and arginase activity in the plasma of cancer patients were analyzed by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  CD14+/CD11b+/HLA-DR- MDSCs were increased in patients with pancreatic or bile duct cancer compared with those in healthy controls, and this increase was correlated with clinical cancer stage. Pancreatic cancer cell lines induced PBMCs to MDSCs in a dose-dependent manner. GM-CSF and arginase activity levels were significantly increased in the serum of patients with pancreatic cancer.
  
  
  CONCLUSIONS
  MDSCs were tumor related: tumor cells induced PBMCs to MDSCs in a dose-dependent manner and circulating CD14+/CD11b+/HLA-DR- MDSCs in pancreatic cancer patients were positively correlated with tumor burden. MDSCs might be useful markers for pancreatic cancer detection and progression.
authors.affiliation: Department of Biliary-Pancreatic Surgery, Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. ryqin@tjh.tjmu.edu.cn.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Peng
authors.forename: Rui
authors.initials: R
authors.lastname: Tian
authors.forename: Xing-Jun
authors.initials: XJ
authors.lastname: Guo
authors.forename: Yu
authors.initials: Y
authors.lastname: Xie
authors.forename: Ren-Yi
authors.initials: RY
authors.lastname: Qin
mesh_terms: D000368:Aged; D001119:Arginase / Q000097:blood; D001650:Bile Duct Neoplasms / Q000097:blood / Q000276:immunology* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000097:blood; D039481:CD11b Antigen / Q000097:blood; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D018281:Cholangiocarcinoma / Q000097:blood / Q000276:immunology* / Q000473:pathology; D018920:Coculture Techniques; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood; D006684:HLA-DR Antigens / Q000097:blood; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000097:blood; D008297:Male; D008875:Middle Aged; D022423:Myeloid Cells / Q000276:immunology* / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000097:blood / Q000276:immunology* / Q000473:pathology; D047368:Tumor Burden; D019139:Tumor Escape
chemical_list: D014408:Biomarkers, Tumor; D039481:CD11b Antigen; D006684:HLA-DR Antigens; C509295:ITGAM protein, human; D018950:Lipopolysaccharide Receptors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D001119:Arginase