title: Fas labeling status does not correlate with apoptosis of renal cell carcinoma in vivo.
abstract: BACKGROUND
  Contribution of the Fas system to apoptosis of renal cell carcinoma (RCC) was investigated in vivo.
  
  
  METHODS
  Tissues from 30 RCC cases were immunostained for Fas and Fas ligand (FasL) to assess associations between Fas labeling status of RCC, indices of FasL-positive tumor-infiltrating mononuclear cells (FasL-TIM) and apoptotic indices (AI) of RCC.
  
  
  RESULTS
  In all cases, tumor cells co-expressed Fas and FasL; strongly and diffusely in 13 cases (43%) and weakly in 17 (57%). Despite the constitutive co-expression of Fas and FasL, AI was low in most cases (median, 7 per 1,000 tumor cells; range, 1 to 257). The Fas labeling status did not significantly associate with AI while FasL-TIM index positively correlated with AI.
  
  
  CONCLUSIONS
  These results suggest that the Fas system is not the principal mechanism of apoptosis of RCC while activated tumor-infiltrating mononuclear cells induce apoptosis via mechanisms other than the Fas system.
authors.affiliation: Department of Urology, Dokkyo University School of Medicine, Shimotsuga-gun, Tochigi, Japan. f-koga@wine.plala.or.jp
authors.forename: F
authors.initials: F
authors.lastname: Koga
authors.forename: K
authors.initials: K
authors.lastname: Arai
authors.forename: T
authors.initials: T
authors.lastname: Kamai
authors.forename: H
authors.initials: H
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D002292:Carcinoma, Renal Cell / Q000378:metabolism / Q000473:pathology*; D053222:Fas Ligand Protein; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000502:physiology; D008875:Middle Aged; D009367:Neoplasm Staging; D019014:fas Receptor / Q000096:biosynthesis* / Q000502:physiology
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D019014:fas Receptor