Relaxin signaling in uterine fibroids.

Uterine fibroid is the most common tumor of female reproductive organs. The role of relaxin signaling in leiomyoma development was analyzed. We used 23 matched pairs of leiomyoma and normal myometrium samples to compare the expression of relaxin family peptide receptors RXFP1 and RXFP2, caveolin 1, desmin, and steroid receptors and their cofactors, NCOR1 and NCOR2. The expression of RXFP1, evaluated by quantitative reverse transcription-PCR, was downregulated in fibroid tissues. Relaxin or insulin-like peptide 3 treatment suppressed transforming growth factor beta-induced phosphorylation of SMAD2 in rat leiomyoma ELT-3 cells in vitro, suggesting a possible involvement of relaxins in the etiology of leiomyoma.