Ovarian Cancer-Associated Mesothelial Cells: Transdifferentiation to Minions of Cancer and Orchestrate Developing Peritoneal Dissemination

Simple Summary Ovarian cancer has a poor prognosis and tends to develop peritoneal dissemination. It is becoming increasingly clear that mesothelial cells that cover the peritoneal cavity are involved in ovarian cancer progression. Mesothelial cells are numerous in the peritoneal cavity and normally play many functions to maintain the peritoneal environment. In the tumor microenvironment, mesothelial cells that gain mesenchymal features and cooperate with ovarian cancer are called ovarian cancer-associated mesothelial cells, and they must help ovarian cancer cells to adhere to the peritoneum, invade, and disseminate. Elucidating and targeting these processes may improve the prognosis of ovarian cancer, which is difficult to cure. Ovarian cancer has one of the poorest prognoses among carcinomas. Advanced ovarian cancer often develops ascites and peritoneal dissemination, which is one of the poor prognostic factors. From the perspective of the "seed and soil" hypothesis, the intra-abdominal environment is like the soil for the growth of ovarian cancer (OvCa) and mesothelial cells (MCs) line the top layer of this soil. In recent years, various functions of MCs have been reported, including supporting cancer in the OvCa microenvironment. We refer to OvCa-associated MCs (OCAMs) as MCs that are stimulated by OvCa and contribute to its progression. OCAMs promote OvCa cell adhesion to the peritoneum, invasion, and metastasis. Elucidation of these functions may lead to the identification of novel therapeutic targets that can delay OvCa progression, which is difficult to cure.