title: Specific p53 immunostaining patterns are associated with smoking habits in patients with oral squamous cell carcinomas.
abstract: OBJECTIVE
  To identify immunostaining patterns that are predictive for p53 mutations and to investigate whether p53 mutations are associated with established risk factors for oral squamous cell carcinoma (OSCC).
  
  
  METHODS
  Fifty five OSCCs were investigated for p53 protein expression by immunohistochemistry (IHC). Ten of these cases, including five p53 immunopositive and five p53 immunonegative cases, were subjected to microdissection of representative tumour areas followed by sequence analysis for the detection of TP53 mutations.
  
  
  RESULTS
  Paired IHC and sequence analysis revealed that p53 immunoexpression in more than 25% of tumour cells was indicative of TP53 mutations, whereas p53 immunonegativity was not informative. Therefore, for p53 immunohistochemical interpretation, p53 immunonegative cases were excluded from the analysis and the cut off value for p53 immunoexpression was set at 25%. Of the OSCCs showing any p53 immunoexpression, 64% revealed staining in more than 25% of the tumour cells. p53 immunoexpression in more than 25% of the neoplastic cells was significantly associated with smoking but not with alcohol consumption. No significant association with smoking habits was found when OSCCs were dichotomised into p53 immunonegative and p53 immunopositive.
  
  
  CONCLUSIONS
  In OSCCs the following conclusions can be made: (1) p53 immunonegativity is not informative for TP53 mutations; (2) 25% p53 immunopositive cells appears to be a good cut off value to predict TP53 mutations; (3) p53 immunostaining patterns that appeared to be predictive for TP53 mutations were associated with the smoking habits of the patients.
authors.affiliation: Department of Oral and Maxillofacial Surgery/Oral Pathology/ACTA, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands. geus@xs4all.nl
authors.forename: I
authors.initials: I
authors.lastname: Cruz
authors.forename: P J F
authors.initials: PJ
authors.lastname: Snijders
authors.forename: V
authors.initials: V
authors.lastname: Van Houten
authors.forename: M
authors.initials: M
authors.lastname: Vosjan
authors.forename: I
authors.initials: I
authors.lastname: Van der Waal
authors.forename: C J L M
authors.initials: CJ
authors.lastname: Meijer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects / Q000235:genetics / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000235:genetics / Q000378:metabolism*; D005260:Female; D016158:Genes, p53; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000209:etiology / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009363:Neoplasm Proteins / Q000378:metabolism; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D016159:Tumor Suppressor Protein p53