title: Immunohistochemical analysis of mismatch proteins in carcinogenesis of the lower lip.
abstract: OBJECTIVE
  This study investigated the immunohistochemical expression of hMLH1 and hMSH2 proteins in lower lip squamous cell carcinoma (SCC) and actinic cheilitis (AC), to contribute to the understanding of the development of lower lip cancer.
  
  
  RESULTS
  Forty cases of lower lip AC and SCC were studied. Quantitative immunohistochemical analysis was undertaken by counting 1000 cells (positive and negative) in each lesion. Statistical evaluation included Student's t-test and one-way ANOVA. For SCC and AC, the mean number of hMLH1- and hMSH2-positive cells decreased with advanced stage of the lesion. The largest mean number of immunostained cells was observed in AC cases without dysplasia or with mild dysplasia (hMLH1: 721.23 ± 88.116; hMHS2: 781.50 ± 156.93). Intermediate values were obtained for AC with moderate or severe dysplasia (hMLH1: 532.86 ± 197.72; hMHS2: 611.14 ± 172.48). Lower lip SSCs presented the smallest number of positive cells (hMLH1: 255.03 ± 199.47; hMHS2: 518.38 ± 265.68). A statistically significant difference was observed between groups (P < 0.001).
  
  
  CONCLUSIONS
  The results support the hypothesis that changes in the immunoexpression of these mismatch proteins are related to the process of carcinogenesis of the lower lip.
authors.affiliation: Postgraduate Program, Oral Pathology, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Dmitry José de Santana
authors.initials: DJ
authors.lastname: Sarmento
authors.forename: Wagner Leite
authors.initials: WL
authors.lastname: de Almeida
authors.forename: Márcia Cristina da Costa
authors.initials: MC
authors.lastname: Miguel
authors.forename: Lélia Maria Guedes
authors.initials: LM
authors.lastname: Queiroz
authors.forename: Gustavo Pina
authors.initials: GP
authors.lastname: Godoy
authors.forename: Maria Carmen Fontoura Nogueira
authors.initials: MC
authors.lastname: da Cruz
authors.forename: Ericka Janine Dantas
authors.initials: EJ
authors.lastname: da Silveira
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D063646:Carcinogenesis; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D002613:Cheilitis / Q000150:complications / Q000378:metabolism / Q000473:pathology; D053843:DNA Mismatch Repair; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008048:Lip Neoplasms / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D012189:Retrospective Studies
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein
keywords: DNA repair; cheilitis; lip neoplasm; oral cancer; squamous cell carcinoma