title: Analysis of cell cycle regulator proteins in non-small cell lung cancer.
abstract: OBJECTIVE
  Abnormalities of the proteins involved in cell cycle checkpoints are extremely common among almost all neoplasms. This study aimed to investigate the expression of four components of the cell cycle machinery-p21, p16, p53, and proliferating cell nuclear antigen (PCNA)-in non-small cell lung cancer (NSCLC).
  
  
  METHODS
  The expression of p21, p16, p53, and PCNA was examined in 68 well characterised NSCLC specimens using immunohistochemistry. The coregulation of these proteins and their influence on survival were analysed using both univariate and multivariate analyses.
  
  
  RESULTS
  By univariate analysis, the expression of all the proteins examined, except for PCNA, was significantly correlated with survival. In multivariate analysis, the only immunohistochemical parameter able to influence overall survival was p16, confirming the hypothesis that the RB-p16 tumour suppressor pathway is inactivated in most lung cancer samples. Finally, the group of patients with NSCLC who were negative for both p21 and p16 had a significantly shorter overall survival.
  
  
  CONCLUSIONS
  These results suggest that loss of control of cell cycle checkpoints is a common occurrence in lung cancers, and support the idea that functional cooperation between different cell cycle inhibitor proteins constitutes another level of regulation in cell growth control and tumour suppression.
authors.affiliation: Third Division of Infective Diseases, D. Cotugno Hospital, Naples 80100, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Esposito
authors.forename: A
authors.initials: A
authors.lastname: Baldi
authors.forename: G
authors.initials: G
authors.lastname: Tonini
authors.forename: B
authors.initials: B
authors.lastname: Vincenzi
authors.forename: M
authors.initials: M
authors.lastname: Santini
authors.forename: V
authors.initials: V
authors.lastname: Ambrogi
authors.forename: T C
authors.initials: TC
authors.lastname: Mineo
authors.forename: P
authors.initials: P
authors.lastname: Persichetti
authors.forename: G
authors.initials: G
authors.lastname: Liuzzi
authors.forename: V
authors.initials: V
authors.lastname: Montesarchio
authors.forename: E
authors.initials: E
authors.lastname: Wolner
authors.forename: F
authors.initials: F
authors.lastname: Baldi
authors.forename: A M
authors.initials: AM
authors.lastname: Groeger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009363:Neoplasm Proteins; D016159:Tumor Suppressor Protein p53