title: Co-expression of p53 and Ki67 and lack of EBV expression in oral squamous cell carcinoma.
abstract: BACKGROUND
  The objectives of the study were to determine the association between Epstein-Barr virus (EBV) and oral squamous cell carcinoma (OSCC), to compare the expression of p53 and Ki67 between normal oral mucosa, oral hyperkeratosis, oral pre-malignant dysplasia, and OSCC, and to determine the correlation between the expression of p53 and Ki67 in OSCC.
  
  
  METHODS
  The expression of EBV mRNA was studied by in situ hybridization technique in 24 cases of OSCC, and the expression of p53 and Ki67 was investigated by immunohistochemical method in 19 cases of OSCC, 7 cases of oral pre-malignant dysplasia, 6 cases of oral hyperkeratosis, and 5 cases of normal oral epithelium.
  
  
  RESULTS
  None of OSCC cases expressed EBV-encoded RNA (EBER) transcripts. The labeling indices (LI) of p53- and Ki67-positive cells were significantly higher in OSCC than in oral pre-malignant dysplasia, oral hyperkeratosis, and normal oral mucosa (P < 0.05). A significant correlation between the LI of p53- and Ki67-positive cells was observed in OSCC (r = 0.6; P = 0.01).
  
  
  CONCLUSIONS
  These findings suggested that the co-expression of p53 and Ki67 may play roles in carcinogenesis of OSCC and p53 overexpression may promote cell proliferation in OSCC. Furthermore, EBV does not appear to be a risk factor for OSCC particularly in the population of northern Thailand.
authors.affiliation: Department of Odontology and Oral Pathology, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand. iamaroon@yahoo.com
authors.forename: Anak
authors.initials: A
authors.lastname: Iamaroon
authors.forename: Udomrat
authors.initials: U
authors.lastname: Khemaleelakul
authors.forename: Surawut
authors.initials: S
authors.lastname: Pongsiriwet
authors.forename: Jarupan
authors.initials: J
authors.lastname: Pintong
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000821:virology; D002455:Cell Division / Q000235:genetics; D020031:Epstein-Barr Virus Infections / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D007972:Leukoplakia, Oral / Q000473:pathology; D009061:Mouth Mucosa / Q000473:pathology; D009062:Mouth Neoplasms / Q000473:pathology* / Q000821:virology; D011230:Precancerous Conditions / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013785:Thailand; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
chemical_list: D019394:Ki-67 Antigen; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53