Omental milky spots--highly efficient "natural filter" for screening gastric cancer stem cells.

Over the last decades, cancer stem cells (CSCs) have been identified in different solid tumors and three strategies have been employed to identify them as follows: (1) expression of cell surface markers, (2) ability to exclude fluorescent dye Hoescht 33342 in a cell population termed "side population" (SP), and (3) formation of tumorspheres in suspension culture. But these methods focus on a minor subset of tumor cells, initial CSCs are still hidden among them and genuine CSCs have not yet been isolated and purified. Here we propose a new strategy to identify and isolate gastric cancer stem cells--using omental milky spots to screen gastric cancer stem cells in peritoneal metastasis mouse models of gastric cancer. This strategy directly target cancer stem cells--which can cause a new tumor by itself. Omental milky spots and their macrophages become a highly efficient "natural filter" for screening gastric cancer stem cells.