title: Oral squamous cell carcinoma: status of tight junction claudins in the different histopathological patterns and relationship with clinical parameters. A tissue-microarray-based study of 136 cases.
abstract: OBJECTIVE
  Claudins are integral transmembrane proteins of the tight junctions, critical for maintaining cell adhesion and polarity. Alterations in the expression of individual claudins have been detected in carcinomas and appear to correlate with tumour progression.
  
  
  METHODS
  In this study, a panel of anti-claudin antibodies (anti-claudins 1, 2, 3, 4, 5 and 7) was employed to map claudin expression in 136 cases of oral squamous cell carcinoma (OSCC) organised in a tissue microarray.
  
  
  RESULTS
  Claudins were expressed in a reticular pattern up to the prickle layer in normal mucosal epithelium. In OSCC, claudins were strongly present in well-differentiated tumours, they presented mild and low expression in moderately differentiated OSCC, and were negative in poorly differentiated OSCC; the absences of claudin 1 (p=0.002) and claudin 4 (p<0.001) were associated with moderately/poorly differentiated tumours. Strong expression of claudin 4 was associated with decreased perineural infiltration (p=0.024). Claudins 5 and 7 were mostly negative or weakly expressed in all cases studied. Expression of claudin 7 was associated with the early clinical stages of the disease, whereas loss of claudin 7 tended to be more frequent in advanced stages of OSCC (p=0.054). Absence of claudin 7 was also associated with absent vascular infiltration (p=0.045) and with presence of recurrence (p=0.052).
  
  
  CONCLUSIONS
  Claudin expression patterns showed a strong correlation with histological type of OSCC; claudin expression was decreased in areas of invasion, and negative in poorly differentiated tumours. This pattern may be related to evolution and prognosis of these tumours, especially in the case of claudin 7, which seems to be associated with a poor prognosis in OSCC.
authors.affiliation: Department of General Pathology, Dental School, University of São Paulo, São Paulo, Brazil. silvialourenco.70@terra.com.br
authors.forename: Silvia V
authors.initials: SV
authors.lastname: Lourenço
authors.forename: Cláudia M
authors.initials: CM
authors.lastname: Coutinho-Camillo
authors.forename: Marcilei E C
authors.initials: ME
authors.lastname: Buim
authors.forename: Cláudia M
authors.initials: CM
authors.lastname: Pereira
authors.forename: André L
authors.initials: AL
authors.lastname: Carvalho
authors.forename: Luiz P
authors.initials: LP
authors.lastname: Kowalski
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Soares
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D057167:Claudins / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006258:Head and Neck Neoplasms / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D019108:Tight Junctions / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D057167:Claudins; D009363:Neoplasm Proteins