title: p16INK4A, CDC6, and MCM5: predictive biomarkers in cervical preinvasive neoplasia and cervical cancer.
abstract: OBJECTIVE
  To analyse and compare expression patterns of three potential biomarkers-p16(INK4A), CDC6, and MCM5-and evaluate their use as predictive biomarkers in squamous and glandular cervical preinvasive neoplasia.
  
  
  METHODS
  Immunocytochemical analysis of p16(INK4A), MCM5, and CDC6 expression was performed on 20 normal, 38 cervical intraepithelial neoplasia 1 (CIN1), 33 CIN2, 46 CIN3, 10 squamous cell carcinoma, 19 cervical glandular intraepithelial neoplasia (cGIN), and 10 adenocarcinoma samples. Staining intensity was assessed using a 0-3 scoring system. p16(INK4A), MCM5, and CDC6 expression was also examined in ThinPrep slides exhibiting mild, moderate, and severe dyskaryosis. Human papillomavirus (HPV) was detected using a modified SYBR green assay. Fluorogenic polymerase chain reaction (PCR) and solution phase PCR were used for specific HPV typing.
  
  
  RESULTS
  All three markers showed a linear correlation between expression and grade of dysplasia. p16(INK4A) and MCM5 protein expression was upregulated in all grades of squamous and glandular dysplasia. CDC6 protein was preferentially expressed in high grade lesions and in invasive squamous cell carcinoma.
  
  
  CONCLUSIONS
  p16(INK4A) expression was closely associated with high risk HPV infection-all grades of squamous and glandular cervical lesions were immunohistochemically positive. MCM5 staining intensity was independent of high risk HPV infection, highlighting its potential as a biomarker in both HPV dependent and independent cervical dysplasia. CDC6 may be a biomarker of high grade and invasive lesions of the cervix, with limited use in low grade dysplasia. p16(INK4A) was the most reliable marker of cervical dysplasia. Combinations of dysplastic biomarkers may be useful in difficult diagnostic cases.
authors.affiliation: Department of Pathology, Coombe Women's Hospital, Dublin 8, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Murphy
authors.forename: M
authors.initials: M
authors.lastname: Ring
authors.forename: C C B B
authors.initials: CC
authors.lastname: Heffron
authors.forename: B
authors.initials: B
authors.lastname: King
authors.forename: A G
authors.initials: AG
authors.lastname: Killalea
authors.forename: C
authors.initials: C
authors.lastname: Hughes
authors.forename: C M
authors.initials: CM
authors.lastname: Martin
authors.forename: E
authors.initials: E
authors.lastname: McGuinness
authors.forename: O
authors.initials: O
authors.lastname: Sheils
authors.forename: J J
authors.initials: JJ
authors.lastname: O'Leary
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000150:complications / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western / Q000379:methods; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000150:complications / Q000276:immunology; D018797:Cell Cycle Proteins / Q000032:analysis* / Q000276:immunology; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000276:immunology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D009363:Neoplasm Proteins / Q000032:analysis / Q000276:immunology; D009687:Nuclear Proteins / Q000032:analysis* / Q000276:immunology; D027383:Papillomaviridae / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000150:complications / Q000175:diagnosis; D012307:Risk Factors; D029702:Schizosaccharomyces pombe Proteins / Q000032:analysis* / Q000276:immunology; D002583:Uterine Cervical Neoplasms / Q000737:chemistry* / Q000150:complications / Q000276:immunology; D002578:Uterine Cervical Dysplasia / Q000737:chemistry* / Q000150:complications / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; C103706:CDC6 protein, human; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; C085711:mcm5 protein, S pombe