title: Expression of hMSH2 and hMLH1 proteins of the human DNA mismatch repair system in salivary gland tumors.
abstract: BACKGROUND
  The human DNA mismatch repair (hMMR) system plays an important role in reducing mutation and maintaining genomic stability. The MMR system in human cells is composed of at least six genes (hMSH2, hMLH1, hMSH3, hPMS1, hPMS2 and GTBP/hMSH6). In particular, hMSH2 and hMLH1 are expressed in cells undergoing rapid renewal; their reduced expression has been reported in several tumors.
  
  
  METHODS
  We examined the expression of hMSH2 and hMLH1 by immunohistochemistry in tumor specimens from 43 patients with primary tumors.
  
  
  RESULTS
  All carcinomas (n = 20) expressed these proteins. In addition, when compared to pleomorphic adenomas, malignant tumors contained significantly (P < 0.01) higher proportions of hMSH2 (56.1 +/- 31.5 vs. 31.1 +/- 22.6) and hMLH1 (27.9 +/- 26.0 vs. 14.0 +/- 12.6) positive cells. Warthin's tumors showed no specific nuclear staining of tumor cells for both hMSH2 and hMLH1.
  
  
  CONCLUSIONS
  These data suggest a minor, if any, role for a defect in the hMMR system in the pathogenesis of malignant salivary gland tumors.
authors.affiliation: Department of Oncology, University of Chieti, Chieti, Italy.
authors.forename: Graziella
authors.initials: G
authors.lastname: Castrilli
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fabiano
authors.forename: Giampiero
authors.initials: G
authors.lastname: La Torre
authors.forename: Luca
authors.initials: L
authors.lastname: Marigo
authors.forename: Chiara
authors.initials: C
authors.lastname: Piantelli
authors.forename: Giorgio
authors.initials: G
authors.lastname: Perfetti
authors.forename: Franco O
authors.initials: FO
authors.lastname: Ranelletti
authors.forename: Mauro
authors.initials: M
authors.lastname: Piantelli
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000235:Adenolymphoma / Q000235:genetics / Q000473:pathology; D008949:Adenoma, Pleomorphic / Q000235:genetics / Q000473:pathology; D000251:Adenosine Triphosphatases / Q000032:analysis* / Q000235:genetics; D020137:Base Pair Mismatch / Q000235:genetics*; D018267:Carcinoma, Acinar Cell / Q000235:genetics / Q000473:pathology; D003528:Carcinoma, Adenoid Cystic / Q000235:genetics / Q000473:pathology; D018277:Carcinoma, Mucoepidermoid / Q000235:genetics / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000648:ultrastructure; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000235:genetics; D005347:Fibroblasts / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D018987:Salivary Ducts / Q000473:pathology; D012468:Salivary Gland Neoplasms / Q000235:genetics / Q000473:pathology*; D018709:Statistics, Nonparametric
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D000251:Adenosine Triphosphatases; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein