title: [The relationship between caspase-3 expression and cell proliferation in rat lung squamous cell carcinoma].
abstract: BACKGROUND
  To analyse the relationship between caspase-3 expression and cell proliferation, and to find molecular-biology markers to adjust canceration during rat lung squamous cell carcinogenesis.
  
  
  METHODS
  The 3-methylcholanthrene(MCA) and diethyinitrosamine (DEN) were used to induce lung squamous cell carcinoma by intra-left lobar-bronchial instillation in 50 Wistar rats, and 10 normal rats as controls. Expression of caspase-3 and PCNA were evaluated by immunohistochemistry (IHC).
  
  
  RESULTS
  Caspase-3 protein positive rate was 44.12% in 34 rat lung squamous cell carcinomas, and positive coefficient value was 1.38±0.95, which were significantly lower than that of normal bronchial epithelium (P=0.007, P < 0.01) and premalignant lesions (P < 0.05, P < 0.05). The mean PCNA-labeling indexes (PCNA-LI) of normal rat bronchial epithelium, premalignant lesions and lung cancer were 14.10±5.02, 28.13±8.72 and 41.88±14.24 (P < 0.05), respectively. There was a negative correlation between caspase 3 and PCNA LI (r=-0.730 6, P < 0.01).
  
  
  CONCLUSIONS
  Loss expression of caspase-3 may promote tumor cell growth, and it may be important in rat lung squamous cell carcinogenesis. Detection of caspase-3 and PCNA proteins can be regarded as major markers in the diagnosis of lung canceration.
authors.affiliation: Department of Pathology, Medical College, Wuhan University, Wuhan, Hubei 430071, P.R.China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Chen
authors.forename: Luming
authors.initials: L
authors.lastname: Diao
authors.forename: Fuchun
authors.initials: F
authors.lastname: Chen
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Ye
authors.forename: Mingqiu
authors.initials: M
authors.lastname: Liu