title: Spontaneous apoptosis in laryngeal squamous cell carcinoma is independent of bcl-2 and bax protein expression.
abstract: BACKGROUND
  bcl-2 and bax genes are known to be involved in the control of apoptotic cell death, an important mechanism of growth regulation that influences the biologic behavior of tumors. The aim of the current study was to investigate the relationship of bcl-2 and bax expression to the rate of spontaneous apoptosis in laryngeal carcinomas, and to assess its relations to clinicopathologic features of tumors.
  
  
  METHODS
  Immunohistochemical analyses for bcl-2 and bax were performed on paraffin embedded tissue sections from 134 primary laryngeal squamous cell carcinomas. To visualize apoptotic cells, the nick end labeling method was used. The proliferative activity of tumors was analyzed by determination of mitotic indices.
  
  
  RESULTS
  bcl-2 immunoreactivity was positively correlated with tumor grade (P < 0.00001), high T category (P < 0.02), metastatic involvement of cervical lymph nodes (P < 0.003), and supraglottic or subglottic location of primary tumors (P < 0.00005). An inverse relation was found between bcl-2 and bax expression (P < 0.004). The frequency of spontaneous apoptosis was closely associated with mitotic activity (P < 0.0004) but appeared to be unrelated to protein levels of bcl-2 or bax as well as to bcl-2:bax ratios.
  
  
  CONCLUSIONS
  The results of this study point to the significance of cell proliferation as a major determinant of the rate of spontaneous apoptosis in laryngeal carcinomas. The bcl-2:bax expression ratio obviously does not affect the incidence of apoptosis, but it may be considered as a marker of disease progression and poor prognosis.
authors: Department of Otorhinolaryngology, Georg-August-University of Göttingen, Germany.
authors: M C
authors: MC
authors: Jäckel
authors: M A
authors: MA
authors: Dorudian
authors: D
authors: D
authors: Marx
authors: U
authors: U
authors: Brinck
authors: A
authors: A
authors: Schauer
authors: W
authors: W
authors: Steiner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D002455:Cell Division; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009333:Neck; D009363:Neoplasm Proteins / Q000378:metabolism*; D009367:Neoplasm Staging; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D016019:Survival Analysis; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein