title: Comparative evaluation of eosinophils in normal mucosa, dysplastic mucosa and oral squamous cell carcinoma with hematoxylin-eosin, Congo red, and EMR1 immunohistochemical staining techniques.
abstract: BACKGROUND
  Oral squamous cell carcinoma is the most common malignant lesion of the oral cavity, and it involves various molecular mechanisms. The development of oral squamous cell carcinoma is influenced by the host immune cells, such as eosinophils. The present study was conducted to compare the presence of eosinophils in normal mucosa, dysplastic mucosa, and oral squamous cell carcinoma by -hematoxylin- eosin staining, Congo red staining, and epidermal growth factor-like (EGF-like) module containing a mucin-like hormone receptor1 (EMR1) immunohistochemical marker.
  
  
  METHODS
  In this cross-sectional study, 60 paraffinized samples were selected, consisting of 20 normal mucosae, 20 dysplastic mucosae, and 20 squamous cell carcinoma samples. After confirmation of the diagnosis, the mean number of eosinophils was evaluated by hematoxylin-eosin, Congo red, and immunohystochemical staining techniques. The data were analyzed by SPSS-10 software using the Kruskal-Wallis and Friedman tests.
  
  
  RESULTS
  The results showed that the number of eosinophils in dysplastic mucosa was significantly higher than the number in normal mucosa, and the number of eosinophils in squamous cell carcinoma was significantly higher than the number in dysplastic mucosa in all staining techniques (p<0.001). Moreover, the comparison of staining techniques showed a significantly higher number of eosinophils in EMR1immunohistochemicalmarker than were observed when Congo red and hematoxylin - eosin (H&E) staining techniques were used (p<0.001).
  
  
  CONCLUSIONS
  It can be argued that eosinophil contributes to the identification of lesions that have a higher potential of malignant transformation. Moreover, eosinophil can be suggested as an indicator in the differentiation of oral lesions in cases with borderline diagnosis and in targeted molecular therapy.
authors.affiliation: Assistant Professor, Dental Implant Research Center and Department of Oral and Maxillofacial Pathology, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Neda
authors.initials: N
authors.lastname: Kargahi
authors.affiliation: Associate Professor, Dental Implant Research Center and Department of Oral and Maxillofacial Pathology, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Sayyed Mohammad
authors.initials: SM
authors.lastname: Razavi
authors.affiliation: Associate Professor, Torabinejad Dental Research Center and Department of Oral and Maxillofacial Pathology, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Parviz
authors.initials: P
authors.lastname: Deyhimi
authors.affiliation: Post Graduate Student, Torabinejad Dental Research Center and Department of Oral and Maxillofacial Pathology, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Homayouni
keywords: Congo red; Dysplastic; EMR1; Eosinophil; Normal mucosa; Squamous cell carcinoma