title: Granulocyte-macrophage colony-stimulating factor inhibits tumor growth during the postoperative period.
abstract: BACKGROUND
  Granulocyte-macrophage colony-stimulating factor (GM-CSF) may have important antineoplastic properties because it induces macrophage tumoricidal activity in vitro. We examined the inhibitory effect of GM-CSF on tumor growth in a murine carcinoma model and whether this inhibitory effect would persist during the postoperative period. Potential macrophage-mediated mechanisms were studied.
  
  
  METHODS
  The effect of GM-CSF on macrophage function in vitro was assessed by measuring superoxide anion and interleukin-6 production, percentage phagocytosis of Candida albicans, and percentage Ia expression. GM-CSF's effect on tumor volume was assessed first in a murine tumor model and second to examine whether these effects also occurred during the postoperative period in the same model after laparotomy. Macrophage function in the latter study was assessed by measuring superoxide anion, cytotoxicity, and tumor necrosis factor production.
  
  
  RESULTS
  GM-CSF treatment was associated with a decrease in tumor volume on day 4 after the initiation of GM-CSF treatment (0.93 +/- 0.08 cm3 for control versus 0.34 +/- 0.08 cm3 for GM-CSF; p < 0.05). This effect was also seen after laparotomy (1.07 +/- 0.2 cm3 for laparotomy+saline versus 0.16 +/- 0.04 cm3 for laparotomy+GM-CSF, p < 0.05). In vivo macrophage function showed increased superoxide anion, cytotoxicity, and tumor necrosis factor-alpha production from macrophages obtained from GM-CSF treated animals compared with saline treated controls.
  
  
  CONCLUSIONS
  Tumor growth is inhibited by GM-CSF treatment, and this effect also occurs after laparotomy. Thus, GM-CSF may have a therapeutic role in the treatment of the tumor bearing host after operation.
authors.affiliation: Department of Surgery, Royal College of Surgeons, Dublin, Ireland.
authors.forename: A D
authors.initials: AD
authors.lastname: Hill
authors.forename: H P
authors.initials: HP
authors.lastname: Redmond
authors.forename: H A
authors.initials: HA
authors.lastname: Naama
authors.forename: D
authors.initials: D
authors.lastname: Bouchier-Hayes
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003131:Combined Modality Therapy; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000627:therapeutic use*; D015850:Interleukin-6 / Q000096:biosynthesis; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000601:surgery*; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000627:therapeutic use; D013154:Spleen; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000970:Antineoplastic Agents; D015850:Interleukin-6; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D016178:Granulocyte-Macrophage Colony-Stimulating Factor