0021-972X/04/$15.00/0 The Journal of Clinical Endocrinology & Metabolism 89(2):823–832 Printed in U.S.A. Copyright © 2004 by The Endocrine Society doi: 10.1210/jc.2003-030874 Hepatocyte Growth Factor/Met System Promotes

ENDOMETRIOSIS, A COMMON disease among women, is a histologically defined, nonmalignant disease in which endometrium-like tissue is found outside the uterus. Endometriosis may exhibit features similar to malignancy, including aggressive growth, localized invasion, and spread to various organs. Sampson’s implantation theory describes a process in which endometrial fragments derived from retrograde menstruation attach, invade, and grow on peritoneal surfaces. This is a widely accepted hypothesis for the pathogenesis of peritoneal endometriosis. Recent studies using implantation models of endometrial cells suggest that endometrial stromal cells are involved in the attachment and early invasion into the peritoneum (1–3). In one study, the invasive phenotype of endometriotic cells was also demonstrated in an in vitro model (4). Thus, the invasion of endometrial stromal cells through the peritoneal surface is an essential step in the development of this disease. We previously reported that several cytokines increase in the peritoneal fluid (PF) of patients with endometriosis and may participate in the pathogenesis of endometriosis (5). Although the invasive process seems to be affected by such factors, the