title: Tumor-associated macrophages in clear cell renal cell carcinoma express both gastrin-releasing peptide and its receptor: a possible modulatory role of immune effectors cells.
abstract: OBJECTIVE
  Renal cell carcinomas (RCC) frequently express the gastrin-releasing peptide receptor (GRP-R). Gastrin-releasing peptide (GRP) stimulates tumor cell proliferation and neoangiogenesis. Tumor-associated macrophages (TAM) comprise an important cellular component of these tumors. We analyzed the GRP/GRP-R network in clear cell RCC (ccRCC) and non-clear cell RCC (non-ccRCC) with special regard to its expression by macrophages, tumor cells and microvessels.
  
  
  METHODS
  Gastrin-releasing peptide and GRP-R expression in 17 ccRCC and 9 non-ccRCC were analyzed by RT-PCR, immunohistochemistry and double immunofluorescence staining.
  
  
  RESULTS
  Tumor-associated macrophages expressed GRP and GRP receptor in ccRCC. Tumor cells and microvessels showed low to intermediate GRP-R expression in nearly all cases. In 12 ccRCC tumor epithelia also expressed low levels of GRP. Microvascular GRP expression was found in nine cases of ccRCC. For non-RCC, the expression of GRP and GRP receptor expression pattern was similar.
  
  
  CONCLUSIONS
  Tumor-associated macrophages are the main source of GRP in RCC. GRP receptor on TAM, tumor epithelia and microvessels might be a molecular base of a GRP/GRP receptor network, potentially acting as a paracrine/autocrine modulator of TAM recruitment, tumor growth and neoangiogenesis.
authors.affiliation: Department of Urology, Eberhard Karls University of Tübingen, Tübingen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Bedke
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hemmerlein
authors.forename: Christina
authors.initials: C
authors.lastname: Perske
authors.forename: Andreas
authors.initials: A
authors.lastname: Gross
authors.forename: Markus
authors.initials: M
authors.lastname: Heuser
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000473:pathology; D045744:Cell Line, Tumor; D015331:Cohort Studies; D005260:Female; D005455:Fluorescent Antibody Technique; D019886:Gastrin-Releasing Peptide / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000276:immunology* / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018004:Receptors, Bombesin / Q000378:metabolism*; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D018004:Receptors, Bombesin; D019886:Gastrin-Releasing Peptide