Stem cells and uterine leiomyomas: What is the evidence?

Uterine leiomyomas, also known as uterine fibroids or uterine myomas, are the most common benign gynecologic tumors found in women of reproductive age. In spite of the numerous published studies evaluating the hormonal dependency, epidemiology, molecular biology, pathology, and genetics of leiomyomas, many questions remain unanswered. The remodeling of the uterus in response to hormonal stimuli and its return to a basal state may be related to adult stem/progenitor cells residing in the endometrial and myometrial layers. Recent published papers on stem cells and their paracrine interactions with more specialized cell populations within leiomyomas may help establish the missing link between the development of treatments designed to stop the growth of leiomyomas and therapies devised to eliminate them. Therefore, this study aimed to address the current paradigm regarding the evidence available on the role of stem/progenitor cells in the pathogenesis of uterine leiomyoma. Only a handful of studies involving humans have been published to date describing the presence of somatic stem cells (SSCs) in the myometrium and leiomyomas. No solid conclusion has been established thus far. Despite the fact that these studies strongly pointed to the vital role human leiomyoma stem cells might play in initiating the development of myomas, huge gaps still persist in the literature. Studies to identify putative myometrial and leiomyoma-specific markers might offer new possibilities for understanding the origin of these tumors and perhaps help develop new nonsurgical noninvasive treatments.