Stem cells in gastric cancer

Figure 1 Hypotheses that explain the cellular heterogeneity, initiation and progression of cancer. A: In the clonal evolution hypothesis, cellular heterogeneity is generated by genetic instability, such as changes in chromosomal number or mutations in the genome of the tumor cells. Those cells with genetic compositions that confer growth advantages will be selected and preferentially expanded; B: In the cancer stem cell (CSC) hypothesis, CSCs reside at the top of the cellular hierarchy and govern tumor heterogeneity. CSCs divide to generate identical CSCs (self-renewal) and differentiate into phenotypically heterogeneous, but usually less proliferative, tumor cells. It is believed that CSCs are often transformed tissue-specific stem cells or de-differentiated transit amplifying progenitor cells.