[Variants of alternatively spliced estrogen receptors].

Many laboratories have been involved in characterization of the estrogen receptors (ER-alfa, ER-beta) with special emphasis on the number of isoforms of this receptors and their role in the pathogenesis of many gynecological disorders. ER isoforms, generated by alternative mRNA splicing have been defined in several tissues and are postulated to play a role in modulating the estrogen response. These splicing variants were shown to act differently from the wild-type receptors and their biological significance remain unknown but same studies have implicated a role of specific isoforms in the pathogenesis of estrogen dependent tissues. Expression of the estrogen receptors, as well as their splicing variants may impact on the biologic properties of same tissues and affect their ability to respond to estrogen and antiestrogen therapies. From the clinical point of view it is importance to know what molecular characteristic of ERs and their isoforms occures in estrogen dependent tissues before histopathological and clinical changes. All of these developments have had a great impact on our understanding of the estrogen action.