title: The expression of estrogen receptor isoforms alpha, beta and insulin-like growth factor-I in uterine leiomyoma.
abstract: BACKGROUND
  A prospective study focusing on leiomyoma was conducted to investigate the expression of estrogen receptor-alpha (ER alpha), estrogen receptor-beta (ER beta) and insulin-like growth factor-I (IGF-I) to elucidate their roles in the pathogenesis of leiomyoma.
  
  
  METHODS
  Twenty-one leiomyomal and six paired myometrial tissues were included in the study. The levels of ER alpha, ER beta and IGF-I mRNAs in leiomyoma and adjacent myometrium were analyzed by quantitative reverse transcription-polymerase chain reaction.
  
  
  RESULTS
  All tissues showed a higher ER alpha expression level. The correlation between ER alpha mRNA and IGF-I mRNA levels was significantly positive (r = 0.527, p = 0.014). The correlation between ER beta mRNA and IGF-I mRNA levels was also positive, but not statistically significant. In six paired leiomyoma and myometrium samples, the levels of ER alpha and ER beta mRNA exhibited no difference, and IGF-I mRNA levels were elevated in leiomyoma compared with paired myometrium (p < 0.05).
  
  
  CONCLUSIONS
  The expression of IGF-I mRNA increases in leiomyoma and ER alpha mRNA is positively correlated with IGF-I mRNA, which implies that estrogen upregulates the gene encoding IGF-I through ER alpha in leiomyoma; ER beta may also be involved in the IGF-I signaling pathway in leiomyoma.
authors.affiliation: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Weiyuan
authors.initials: W
authors.lastname: Zhang
authors.forename: Shaohai
authors.initials: S
authors.lastname: Wang
mesh_terms: D000328:Adult; D047628:Estrogen Receptor alpha / Q000235:genetics* / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism; D007889:Leiomyoma / Q000235:genetics*; D008875:Middle Aged; D009215:Myometrium / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014594:Uterine Neoplasms / Q000235:genetics*
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D020033:Protein Isoforms; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I