title: Immunoexpression of hMSH2 and hMLH1 in oral squamous cell carcinoma and its relationship to histological grades of malignancy.
abstract: BACKGROUND
  The aim of this study was to describe the human mutS homolog 2 (hMSH2) and human mutL homolog 1 (hMLH1) immunoexpression in different areas of oral squamous cell carcinoma (OSCC) - central/superficial (C/S) and invasive tumor front (ITF) - in an attempt to verify if the histological grade of malignancy interferes in this expression.
  
  
  METHODS
  Forty-six samples of OSCC were analyzed histologically. Twenty-six cases (56.5%) presented ITF. Histological grades of malignancy were evaluated in all samples, and immunohistochemistry was applied using specific antibodies against hMSH2 and hMLH1 proteins. Immunoexpression was semiquantitatively scored, and results were correlated with their histological grades of malignancy.
  
  
  RESULTS
  The hMSH2 immunoexpression in both C/S and ITF was not correlated with histological grades of malignancy, whereas hMLH1 overexpression was correlated (P = 0.043) and associated (P = 0.041) with well-differentiated tumors. In addition, hMHL1 reduction or negative expression was detected in poorly differentiated tumors. Moreover, negative expression for hMSH2 and hMLH1 proteins was demonstrated in some cases of OSCC.
  
  
  CONCLUSIONS
  The findings of the present study indicate that the histological grade of malignancy interferes in hMLH1 immunoexpression. The negativity for both hMSH2 and hMLH1 proteins in some cases suggests a possible association between OSCC and hereditary non-polyposis colorectal cancer. Further investigation from future studies is needed to elucidate this supposition.
authors.affiliation: Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
authors.forename: Anacelia Mendes
authors.initials: AM
authors.lastname: Fernandes
authors.forename: Maria Letícia
authors.initials: ML
authors.lastname: Ramos-Jorge
authors.forename: Sergio Vitorino
authors.initials: SV
authors.lastname: Cardoso
authors.forename: Adriano Mota
authors.initials: AM
authors.lastname: Loyola
authors.forename: Ricardo Alves
authors.initials: RA
authors.lastname: Mesquita
authors.forename: Maria Cássia Ferreira
authors.initials: MC
authors.lastname: Aguiar
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology*; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009687:Nuclear Proteins / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein