Biologic factors influencing fibroid growth hormones and cytokines

Leiomyomas are a significant problem in women's health. An understanding of the biologic structure of these tumors and of how their growth is regulated is emerging from analyses of tissue specimens and from in vitro studies using cultured cells. These studies are clarifying the mechanisms by which ovarian steroid hormones regulate the growth of uterine SMCs, and they are clarifying how the ovarian steroid ligand-receptor system has been altered in leiomyomas. Such information will allow investigators to identify steroid hormone antagonists and steroid hormone receptor modulators that may be useful for the treatment of leiomyomas. It is clear that many of the growth-promoting effects of ovarian steroid hormones on leiomyomas are mediated through the actions of specific growth factors. These growth factors regulate the proliferation, apoptosis, and ECM production of the SMCs, and they regulate the proliferation and migration of vascular endothelial cells. Targeting these growth factors and their receptors can reduce leiomyoma growth through two different mechanisms-the SMCs and the vascular system that supports tumor growth. The next few years will undoubtedly yield many new drug discoveries that will lead to new therapies for the treatment of this disease.