title: Loss of BCL-2 in the progression of oral cancer is not attributable to mutations.
abstract: BACKGROUND
  BCL-2 and BAX are important in the regulation of apoptosis. There have been reports of loss of BCL-2 in basal cells of oral epithelial dysplasia (OED) and in oral squamous cell carcinoma (OSCC), and suppression of BAX in poorly differentiated OSCC.
  
  
  OBJECTIVE
  To investigate whether loss of BCL-2 in OED and OSCC, and of BAX in poorly differentiated OSCC could be attributed to BCL-2 and BAX mutations.
  
  
  METHODS
  Immunohistochemistry and in situ hybridisation were used to confirm BCL-2 and BAX expression. DNA was extracted from archival samples of OED (n = 22) and OSCC (n = 28). The connective tissue part from each section was collected separately and used as the normal reference.
  
  
  RESULTS
  No mutations were detected in BCL-2 or BAX that could explain their aberrant expression at the mRNA and protein levels in OED and OSCC. The reported A/G polymorphism at codon 7 of BCL-2 was detected in 18 of 50 samples and a novel C/T polymorphism at codon 100 was detected in three of 50 samples.
  
  
  CONCLUSIONS
  No mutations were found that could explain loss of BCL-2 in oral dysplasia and carcinoma. An unreported C/T polymorphism in BCL-2 was detected. Downregulation of BCL-2 in OED and OSCC may be the result of transcriptional regulation.
authors.affiliation: Department of Odontology-Oral Pathology and Forensic Odontology, Haukeland University Hospital, N5021 Bergen, Norway.
authors.forename: L L
authors.initials: LL
authors.lastname: Loro
authors.forename: A C
authors.initials: AC
authors.lastname: Johannessen
authors.forename: O K
authors.initials: OK
authors.lastname: Vintermyr
mesh_terms: D001483:Base Sequence; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D018450:Disease Progression; D015870:Gene Expression; D019254:Genes, bcl-2; D006801:Humans; D009062:Mouth Neoplasms / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D011230:Precancerous Conditions / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C494826:BAX protein, human; D004273:DNA, Neoplasm; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D051028:bcl-2-Associated X Protein