**Abstract**

Gastric stem cells have been recently identified and are not yet fully characterized. Each gastric gland or unit is composed of different specialized cells and a small number of discrete stem cells. These gastric stem cells play key roles. They have self-renewal and multipotent properties and are the origin of specialized gastric epithelial cells. These properties are the basis for the stem cells' role in tissue homeostasis, tissue repair, and cancer. In tumors, growing evidence indicates that a cell subpopulation with stem cell features, the so-called cancer stem cells (CSCs), represents the "fuel" for the tumor: they are at the origin of tumor initiation, growth, and dissemination, and they also display resistance to conventional chemotherapy treatments. The recent identification of CSCs in gastric carcinoma opens the door to the development of new therapeutic strategies targeting more specifically the CSCs at the origin of the disease, which is the third leading cause of cancer-related deaths worldwide.

**Keywords:** stem cells, gastric cancer stem cells, CD44, stomach cancer, *Helicobacter pylori*, chemoresistance, ALDH, markers
