(PQA3) Why is Ovarian Cancer Primarily a Disease of Postmenopausal Women

 描述(申请人提供)：上皮性卵巢癌主要是绝经后妇女的疾病，80%-90%的卵巢癌病例发生在40岁之后。绝经高峰期出现在51岁，而浸润性上皮性卵巢癌的高发期出现在63岁。绝经后卵巢癌的发病机制有许多学说，包括持续的排卵和炎症、激素变化、免疫功能低下、细胞衰老加剧和活性氧的产生不受控制。对卵巢癌的始发事件缺乏了解，严重阻碍了我们对卵巢癌早期发现和预防的努力。越来越多的人接受卵巢癌实际上起源于输卵管，恶性细胞脱落到邻近的卵巢。由于大部分肿瘤通常形成在卵巢，而不是输卵管，卵巢在癌症发展的早期阶段肯定扮演着重要的角色。流行病学数据一致表明，卵巢癌的风险随着排卵周期的增加而增加，这表明排卵在卵巢癌的病因中起着一定的作用。然而，矛盾的是，女性通常在最后一次排卵后十多年患上卵巢癌。在绝经后的几年中，卵巢卵泡耗尽，剩余的卵巢大部分被重塑，形成纤维化的疤痕组织。与目前认为萎缩的卵巢是一种无功能的纤维性瘢痕相反，我们假设绝经后卵巢富含胶原的微环境为种植肿瘤输卵管细胞提供了肥沃的土壤。这一假说是基于纤维化和胶原蛋白的公认作用 重塑在促进几种癌症类型的肿瘤发生中的作用，以及我们最近发现，在卵巢癌进展和卵泡退化过程中，相似的胶原蛋白重塑基因组被丰富。为了验证我们的假设，我们将首先确定哪些分子事件与人类卵巢老化和绝经状态有关(目标1)，然后在小鼠模型中测试卵巢老化和/或纤维化是否有助于增加输卵管细胞在卵巢中的植入(目标2)。我们假设的证据将重塑目前关于卵巢癌病因学的范式。此外，确定哪些细胞和分子过程促进和抑制癌细胞植入卵巢将提供必要的洞察，以识别预防和早期发现的靶点。

 DESCRIPTION (provided by applicant): Epithelial ovarian cancer is predominantly a disease of postmenopausal women, with 80-90% of ovarian cancer cases occurring after the age of 40. The peak incidence of menopause occurs at age 51, while the peak incidence of invasive epithelial ovarian cancer occurs at age 63. Many theories of postmenopausal onset of ovarian cancer have been proposed, including incessant ovulation and inflammation, hormonal changes, reduced immunity, increased cell senescence and uncontrolled production of reactive oxygen species. A poor understanding of the initiating events in ovarian cancer has significantly hampered our efforts towards early ovarian cancer detection and prevention. It is increasingly accepted that ovarian cancer actually originates in the fallopian tube with malignant cells shedding to the adjacent ovary. Since the bulk of the tumor typically forms in the ovary, rather than the fallopian tube, ovaries must play a significant role in the early stages of cancer development. Epidemiologic data consistently show that ovarian cancer risk increases with the number of ovulatory cycles, indicating that ovulation plays a role in ovarian cancer etiology. However, it is paradoxical that women typically develop ovarian cancer more than a decade after their last ovulation. During the postmenopausal years, the ovarian follicles are depleted and much of the remaining ovary is remodeled to form fibrotic scar tissue. In contrast to the current view of the atrophic ovary as a nonfunctional fibrotic scar, we postulate that the collagen-rich microenvironment of the postmenopausal ovary provides fertile soil for the seeding of neoplastic tubal cells. This hypothesis is based on the recognized role of fibrosis and collagen remodeling in facilitating tumorigenesis in several cancer types and on our recent finding that similar sets of collagen- remodeling genes are enriched during ovarian cancer progression and ovarian follicle regression. To test our hypothesis, we will first identify which molecular events are associated with human ovarian aging and menopausal status (Aim 1) and then test in a mouse model whether ovarian aging and/or fibrosis contribute to increased implantation of tubal cells into the ovary (Aim 2). Proof of our hypothesis will re-shape the current paradigms about ovarian cancer etiology. Moreover, determining which cellular and molecular processes promote and inhibit implantation of cancer cells into the ovary will provide needed insight into the identiy of targets for prevention and early detection.