Читать книгу The SAGE Encyclopedia of Stem Cell Research - Группа авторов - Страница 277

CSCs are tumor cells, with properties similar to normal stem cells, such as the ability to give rise to all cell types found in a particular cancer sample. CSCs are tumor-forming cells and may generate tumors through the stem cell processes of self-renewal and differentiation into multiple cell types. Such cells are proposed to persist in tumors as a distinct population and cause recurrence and spread of tumor by giving rise to new tumors. Cancer stem cell research is focused on developing methods to control the disease by targeting these cells.

CSCs, unlike the other cells that form the bulk of a tumor, can self-perpetuate and produce progenitor cells that can repopulate tumor cells eradicated by treatments such as chemotherapy or radiation. These properties allow cancer stem cells to resist all sorts of treatments including chemotherapy, radiotherapy, and molecular-targeted therapy. Evidence of CSC existence is much stronger for hematologic malignancies because this area is better researched as compared to solid organs.

Figure 1 Stem cell characteristics

There are two models for CSC renewal. The cancer stem cell model refers to a subset of tumor cells (CSCs) that have the ability to self-renew and are able to generate the diverse tumor cells. It is believed that only these cells can generate a tumor. The clonal evolution model postulates that tumor cells with a growth potential are selected and expanded. Cells in the dominant population have a similar potential for initiating tumor growth. In the clonal evolution model, all undifferentiated cells have similar possibility to change into tumorigenic cells.

Figure 2 A normal cellular hierarchy comprising stem cells at the apex, which generate common and more restricted progenitor cells and ultimately the mature cell types that constitute particular tissues

Figure 3 In the cancer stem cell (CSC) model, only the CSCs have the ability to generate a tumor, based on their self-renewal properties and proliferative potential

Figure 4 In the clonal evolution model, all undifferentiated cells have similar possibility to change into a tumorigenic cell