[Protein expression of human progesterone receptor isoforms A and B in uterine leiomyoma].

OBJECTIVE

To investigate the role of two isoforms of human progesterone receptor A (hPR-A) and B (hPR-B) in the development of uterine leiomyoma, their distribution and expression in leiomyoma were detected.

METHODS

The tissues of leiomyoma and normal myometrium from 30 uteri, which were excised for leiomyoma, were used for the localization and quantification of protein of the two isoforms. Immunohistochemistry and Western blot were applied respectively.

RESULTS

Both hPR-A and hPR-B were nuclear receptors. Concentrations of hPR-(A + B) and hPR-A in leiomyoma were higher than those in normal myometrium (295,796 +/- 90,856, 256,275 +/- 98,560; P = 0.042, P = 0.000,563). Both isoforms were presented in leiomyoma and normal myometrium, with a consistent dominance of hPR-B over hPR-A. More expression of hPR-A was found during secretive phase than proliferative phase, not only in leiomyoma but also in normal myometrium (P = 0.037, P = 0.024).

CONCLUSIONS

The development of uterine leiomyoma seems to be related with the progesterone receptor isoforms, especially hPR-A.