title: Association between langerhans cells population and histological grade of oral squamous cell carcinoma.
abstract: BACKGROUND
  Langerhans cells (LCs) are a unique population of antigen processing cells in the epidermis and mucous membrane, which may play a role in the defence mechanism against epithelial tumors.
  
  
  OBJECTIVE
  To compare the distribution of LCs in oral squamous cell carcinomas (OSCC) and normal oral epithelium; and to determine whether the population of LCs in OSCC has any correlation with histological grading of these malignancies.
  
  
  METHODS
  A cross-sectional immunohistochemical analysis of OSCC cases.
  
  
  METHODS
  Forty-eight randomly selected paraffin tissue blocks of OSCC cases and 30 cases of normal oral epithelium were included. Hematoxylin and eosin-stained sections of the OSCC cases were reviewed and categorized as high-grade malignant tumors or low-grade malignant tumors. Tissue sections were analyzed for density of LCs using CD1a antibody expression.
  
  
  METHODS
  Data are expressed as percentages compared by Chi-square statistics; mean ± standard deviation, compared by Mann-Whitney-U test and Spearman's correlation tests.
  
  
  RESULTS
  LCs population was significantly higher in normal oral epithelium when compared with OSCC cases (P = 0.001). There was also a significant difference in the number of LCs per millimetre square area of tissue section between well-differentiated tumors and poorly-differentiated tumours (P = 0.03). There was a negative correlation between the population density of LCs and the grade of OSCC.
  
  
  CONCLUSIONS
  These findings suggest that oral mucosal LCs are involved in immune-surveillance and immunologic impairment may characterize invasive OSCC. In addition, LCs density characterizes histological grades of OSCC, which may be of a prognostic value.
authors.affiliation: Department of Physiology and Oral Pathology, University of Ibadan/University College Hospital, Ibadan, Nigeria.
authors.forename: Taye J
authors.initials: TJ
authors.lastname: Lasisi
authors.affiliation: Department of Pathology, University of Ibadan/University College Hospital, Ibadan, Nigeria.
authors.forename: Abideen O
authors.initials: AO
authors.lastname: Oluwasola
authors.affiliation: Department of Otorhinolarynlogy, University of Ibadan/University College Hospital, Ibadan, Nigeria.
authors.forename: Olawale A
authors.initials: OA
authors.lastname: Lasisi
authors.affiliation: Department of Pathology, University of Ibadan/University College Hospital, Ibadan, Nigeria.
authors.forename: Effiong E
authors.initials: EE
authors.lastname: Akang
keywords: CD1a; langerhans cells; oral squamous cell carcinoma