61. Omental milky spots screening gastric cancer stem cells

Many strategies have been employed to isolate and identify cancer stem cells (CSCs), but these methods only focus cancer stem cells on a minor subset of tumor cells, instead of initial CSCs and progenitor cells. How to target and isolate initial CSCs and progenitor cells is the key further study. Omental milky spots provide a model which let us target gastric cancer stem cells. Omental milky spots are composed of numerous macrophage and lymphocyte aggregation and are involved in the clearance of particles, bacteria and tumor cells from the peritoneal cavity. Many studies have indicated that gastric cancer cells selectively infiltrate into the milky spots in the early stage of peritoneal cancer dissemination, and then from micrometastasis. In this study, we used the property that the macrophages in omental milky spots have cytotoxic aganist tumor cells to screen and collect cancer stem cells. Our finding suggest that macrophages in omental milkey spots not only have cytotoxic properties against tumor cells but also provide a microenvironment within milky spots in which cancer stem cells are capable of survival and growth into micrometastasis. Omental milky spots become a cancer stem cell niche in this situation. We further study the Omental milky spots screening gastric cancer cells (OMSSGCCs) and find Omental milky spots enriched the gastric stem cells. Tumor were consistently generated after an injection of 1×103 OMSS-GCCs high express CD133 and low express CD324, Omental milky spots are a highly efficient “natural filter” for screening gastric cancer stem cells.