title: mRNA expression of the DNA replication-initiation proteins in epithelial dysplasia and squamous cell carcinoma of the tongue.
abstract: BACKGROUND
  The tongue squamous cell carcinomas (SCCs) are characterized by high mitotic activity, and early detection is desirable. Overexpression of the DNA replication-initiation proteins has been associated with dysplasia and malignancy. Our aim was to determine whether these proteins are useful biomarkers for assessing the development of tongue SCC.
  
  
  METHODS
  We analyzed the mRNA expression of CDC6, CDT1, MCM2 and CDC45 in formalin-fixed, paraffin-embedded benign and malignant tongue tissues using quantitative real-time PCR followed by statistical analysis.
  
  
  RESULTS
  We found that the expression levels are significantly higher in malignant SCC than mild precancerous epithelial dysplasia, and the expression levels in general increase with increasing grade of precancerous lesions from mild, moderate to severe epithelial dysplasia. CDC6 and CDC45 expression is dependent of the dysplasia grade and lymph node status. CDT1 expression is higher in severe dysplasia than in mild and moderate dysplasia. MCM2 expression is dependent of the dysplasia grade, lymph node status and clinical stage. The expression of the four genes is independent of tumor size or histological grade. A simple linear regression analysis revealed a linear increase in the mRNA levels of the four genes from the mild to severe dysplasia and SCC. A strong association was established between CDC6 and CDT1, and between MCM2 and CDC45 expression. The nonparametric receiver operating characteristic analysis suggested that MCM2 and CDC45 had a higher accuracy than CDC6 and CDT1 for distinguishing dysplasia from tongue SCC.
  
  
  CONCLUSIONS
  These proteins can be used as biomarkers to distinguish precancerous dysplasia from SCC and are useful for early detection and diagnosis of SCC as an adjunct to clinicopathological parameters.
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China. christina0125@163.com
authors.forename: Jian-na
authors.initials: JN
authors.lastname: Li
authors.forename: Chong-jin
authors.initials: CJ
authors.lastname: Feng
authors.forename: Yong-jun
authors.initials: YJ
authors.lastname: Lu
authors.forename: Hui-jun
authors.initials: HJ
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Tu
authors.forename: Gui-qing
authors.initials: GQ
authors.lastname: Liao
authors.forename: Chun
authors.initials: C
authors.lastname: Liang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000235:genetics*; D004261:DNA Replication; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D064111:Minichromosome Maintenance Complex Component 2; D009687:Nuclear Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014062:Tongue Neoplasms / Q000235:genetics* / Q000473:pathology; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C113571:CDC45 protein, human; C103706:CDC6 protein, human; C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; C084859:MCM2 protein, human; D064111:Minichromosome Maintenance Complex Component 2