[Effects of mifepristone on gene expression of epidermal growth factor in human uterine leiomyoma].

OBJECTIVES: To study the effects of mifepristone on epidermal growth factor gene expression in human uterine leiomyoma. METHODS: 20 patients with leiomyoma were divided into two groups. One was control group who underwent hysterectomy because of leiomyoma, the other was experimental group who underwent hysterectomy after pretreatment with mifepristone 10 mg/daily for 3 months. Epidermal growth factor (EGF) mRNA was semiquantified in samples of leiomyoma and adjacent normal myometrium from patients untreated in different phases of menostrual cycle and from those treated with mifepristone. Semiquantitative reverse transcriptase polymerase chain reaction, using beta-actin as internal standard, was applied to determine levels of EGF mRNA. RESULTS: Leiomyoma untreated with mifepristone had significantly greater amounts of EGF mRNA than adjacent normal myometrium of uterus only in the luteal phase, but not in the follicular phase of cycle. Similarly, leiomyoma untreated with mifepristone also had significantly larger amount of EGF mRNA than treated leiomyoma in the luteal phase of the cycle, whereas, no difference in the follicular phase of the cycle. CONCLUSION: These findings suggested that: (1) EGF mRNA levels in leiomyoma were increased only in the luteal phase, therefore, maybe mainly controlled by progesterone; (2) mifepristone inhibited EGF gene expression in leiomyoma. This may be one of regression mechanism of uterine leiomyoma in response to the antiprogesterone mifepristone.