**3.2. Definition of cancer stem cells (CSCs)**

As defined by the American Association for Cancer Research Workshop on Cancer Stem Cells, a cancer stem cell (CSC) is a cell within a tumor that possesses the capacity to self-renew and to give rise to the heterogeneous lineages of cancer cells that comprise the tumor. Because they have an intrinsic ability to propagate tumor cells, CSCs are also referred to as "tumorinitiating cells" or "tumorigenic cells" [21]. The ability of stem cells to self-renew and give rise to multiple cell lineages is termed as "stemness" [22] (**Table 1**).

#### 248 Gastric Cancer


**Table 1.** Characteristics of the cancer stem cells [21].
