Coordinated regulation of HOX gene expression in myometrium and uterine leiomyoma.

OBJECTIVE: To measure HOXA10 gene expression in uterine myometrium and leiomyoma throughout the menstrual cycle.
DESIGN: HOXA10 gene expression was measured in paired myometrium and leiomyoma from the same uterus.
SETTING: University medical center. PATIENT(S): Thirty-one patients with leiomyoma. INTERVENTION(S): Collection of leiomyoma and myometrial tissue during hysterectomy. MAIN OUTCOME MEASURE(S): HOXA10 gene expression was analyzed by Northern analysis and quantified by laser densitometry. RESULT(S): Both myometrium and leiomyoma continued to express HOXA10 in the adult and menstrual cycle stage-specific regulation was evident in both tissues. During the mid-secretory phase of the menstrual cycle, HOXA10 expression decreased in both leiomyoma and myometrium. At all points in the menstrual cycle HOXA10 expression in leiomyoma was similar to expression in paired myometrium. CONCLUSION(S): HOXA10 is expressed in both myometrium and leiomyoma. Coordinated regulation of this transcript factor suggests similar gene activation in both leiomyoma and myometrium. Diminished expression of HOXA10, a gene that normally causes differentiation, may allow increased growth resulting in the increased mitosis seen in the secretory phase. The identification of this developmental control gene in myometrium and leiomyoma may lead to a better understanding of the molecular mechanisms responsible for growth and differentiation of these tissues.