Search

Background: Epithelial ovarian cancer (EOC) risk correlates strongly with the number of ovulations that a woman experiences. The primary source of EOC in women is the ovarian surface epithelium (OSE). Mechanistic studies on the etiology of OSE transformation to EOC cannot be realistically performed in women. Selecting a suitable animal model to investigate the normal OSE in the context of ovulation should be guided by the model's reproductive similarities to women in natural features that are thought to contribute to EOC risk.Methods: We selected the non-human primate, rhesus macaque, as a surrogate to study the normal OSE during the natural menstrual cycle. We investigated OSE morphology and marker expression, plus cell proliferation and death in relation to menstrual cycle stage and ovulation.Results: OSE cells displayed a morphological range from squamous to columnar. Cycle-independent parameters and cycle-dependent changes were observed for OSE histology, steroid receptor expression, cell death, DNA repair and cell adhesion. Contrary to findings in non-primates, primate OSE cells were not manifestly cleared from the site of ovulation, nor were proliferation rates affected by ovulation or stage of the menstrual cycle. DNA repair proteins were more highly expressed in OSE than in other ovarian cells.Conclusions: This study identifies significant differences between primate and non-primate OSE. In contrast to established views, ovulation-induced death and proliferation are not indicated as prominent contributors to EOC risk, but disruption of OSE cadherin-mediated adhesion may be, as could the loss of ovary-mediated chronic suppression of proliferation and elevation of DNA repair potential. [ABSTRACT FROM AUTHOR]

Background: The fifth leading cause of cancer deaths among women is ovarian cancer (OC), which originates primarily in the ovarian surface epithelium (OSE) that surrounds the ovary. Permanent removal of the OSE could provide a novel strategy to substantially reduce OC risk, while retaining the benefits of ovarian function, including gameto- and steroidogenesis. It must be determined whether ovarian surface epitheliectomy (OSEx) carries deleterious side effects, including loss of menstrual cyclicity, infertility or scarring (e.g. adhesions), prior to any clinical application of this strategy. To achieve this, we selected the non-human primate, rhesus macaque, for long-term (12 month) studies on the effects of OSEx.Methods: Rhesus macaque females underwent OSEx by detergent treatment and were then monitored for menstrual cyclicity (menstruation, steroidogenesis and follicle development) and adverse side effects (tissue scarring or adhesions). Ovaries were collected at 6 or 12 months and examined for evidence of tissue damage, follicle rupture and regression of the corpus luteum. The ovarian surface was examined immunohistologically for signs of epithelial replacement, using markers for OSE and fimbrial epithelium (FE), a possible alternative source of pelvic tumors diagnosed as OC.Results: After OSEx, menstrual cycle length, estrogen and progesterone production, follicle rupture and luteal regression appeared normal. No evidence of adhesions was seen. At 6 and 12 months post-OSEx, the ovarian surface was sparsely populated by cells expressing OSE and FE markers. Proliferative activity in this population was notably low.Conclusions: OSEx may provide a novel method to reduce the risk of OC, without sacrificing ovarian function, although the effects on fertility remain to be tested. The absence of epithelial replacement via enhanced proliferation suggests OSEx does not increase malignant potential. Complete and permanent OSEx may be feasible. [ABSTRACT FROM AUTHOR]