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-α (ERα), estrogen receptor-β (ERβ) 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 ERα, ERβ and IGF-I mRNAs in leiomyoma and adjacent myometrium were analyzed by quantitative reverse transcription-polymerase chain reaction.

Results. All tissues showed a higher ERα expression level. The correlation between ERα mRNA and IGF-I mRNA levels was significantly positive (r = 0.527, p = 0.014). The correlation between ERβ mRNA and IGF-I mRNA levels was also positive, but not statistically significant. In six paired leiomyoma and myometrium samples, the levels of ERα and ERβ 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 ERα mRNA is positively correlated with IGF-I mRNA, which implies that estrogen upregulates the gene encoding IGF-I through ERα in leiomyoma; ERβ may also be involved in the IGF-I signaling pathway in leiomyoma.

Keywords:

• Estrogen receptor-α/β
• insulin-like growth factor-I
• mRNA
• uterus
• leiomyoma