title: Altered expression pattern of alternatively spliced estrogen receptor beta transcripts in breast carcinoma.
abstract: Dysregulation of total estrogen receptor beta (ERbeta) expression has been implicated in breast tumorigenesis. The ERbeta gene yields five exon 8 alternatively spliced transcripts (ERbeta1-5), which encode proteins with different C-terminal amino acids. Individual expression analysis of these transcripts may provide new insights into estrogen signaling in breast cancer. We measured mRNA levels of total ERbeta and its five isoforms in normal tissues, breast carcinomas from post-menopausal patients, and breast cancer cell lines by means of real-time reverse transcription-polymerase chain reaction and fluorescent fragment analysis. In various normal human tissues, ERbeta1-5 isoforms displayed different qualitative and quantitative expression patterns that were consistent with previous reports. Total ERbeta mRNA levels were significantly lower in breast tumors than in normal breast tissues (38-fold lower, P < 0.001), mainly due to lower expression of ERbeta1 and ERbeta2 (ERbeta5 expression was similar in the two tissue types). This altered expression pattern of ERbeta isoforms in breast cancer should be taken into account in future ERbeta-based clinical applications.
authors.affiliation: Laboratoire d'Oncogénétique--INSERM E0017, Centre Rene Huguenin, F-92211 St-Cloud, France.
authors.forename: Igor
authors.initials: I
authors.lastname: Girault
authors.forename: Catherine
authors.initials: C
authors.lastname: Andrieu
authors.forename: Sengül
authors.initials: S
authors.lastname: Tozlu
authors.forename: Fréderique
authors.initials: F
authors.lastname: Spyratos
authors.forename: Ivan
authors.initials: I
authors.lastname: Bièche
authors.forename: Rosette
authors.initials: R
authors.lastname: Lidereau
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D001483:Base Sequence; D001940:Breast / Q000378:metabolism* / Q000473:pathology; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D047629:Estrogen Receptor beta; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D047629:Estrogen Receptor beta; D020033:Protein Isoforms; D012333:RNA, Messenger; D011960:Receptors, Estrogen