title: Hypersensitive K303R oestrogen receptor-alpha variant not found in invasive carcinomas.
abstract: BACKGROUND
  Genetic abnormalities or mutations in premalignant breast lesions may have a role in progression toward malignancy or influence the behaviour of subsequent disease. The A908G (Lys303-->Arg) change in the gene encoding oestrogen receptor-alpha (ER-alpha) creates a hypersensitivity to oestradiol and would have significant consequences if present in breast carcinoma, especially those treated with endocrine therapy. We have therefore examined a panel of endocrine-treated invasive carcinomas for the presence of this mutation.
  
  
  METHODS
  Sequencing of control DNA was shown to detect mutation present in as little as 15% of the starting material. Enrichment for the mutation by using MboII restriction digestion allowed the detection of mutant present at 1% or less. We applied these techniques to genomic DNA and cDNA from 136 invasive breast carcinomas.
  
  
  RESULTS
  No evidence of the A908G mutation was found with either technique. The incidence of this mutation in our panel of tumours is therefore significantly less than previously reported.
  
  
  CONCLUSIONS
  The fact that the mutation was not found leads us to believe that this mutation is absent from most cells in invasive carcinomas and furthermore that the major expression product of the ER-alpha gene in cancers does not contain the K303R mutation. It is therefore unlikely to influence the effectiveness of endocrine treatment.
authors.affiliation: Clatterbridge Cancer Research Trust, JK Douglas Laboratories, Clatterbridge Hospital, Bebington, Wirral, UK. miked@ccrt.nhs.uk
authors.forename: Michael P A
authors.initials: MP
authors.lastname: Davies
authors.forename: Penny A
authors.initials: PA
authors.lastname: O'Neill
authors.forename: Helen
authors.initials: H
authors.lastname: Innes
authors.forename: D Ross
authors.initials: DR
authors.lastname: Sibson
mesh_terms: D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics* / Q000503:physiopathology; D002277:Carcinoma / Q000235:genetics* / Q000503:physiopathology; D002471:Cell Transformation, Neoplastic; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D004958:Estradiol / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000235:genetics*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D016133:Polymerase Chain Reaction / Q000379:methods; D017698:Postmenopause; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
chemical_list: D018931:Antineoplastic Agents, Hormonal; D004273:DNA, Neoplasm; D047628:Estrogen Receptor alpha; D004958:Estradiol