Cancer stem cell

Cancer stem cells (CSCs) are cancer cells that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. CSCs are therefore tumorigenic (tumor-forming), perhaps in contrast to other non-tumorigenic cancer cells. CSCs may generate tumors through the stem cell processes of self-renewal and differentiation into multiple cell types. Such cells are hypothesized to persist in tumors as a distinct population and cause relapse and metastasis by giving rise to new tumors. Therefore, development of specific therapies targeted at CSCs holds hope for improvement of survival and quality of life of cancer patients, especially for patients with metastatic disease.

Characteristics

Cancer stem cells are a subpopulation of cancer cells that can self-renew, initiate tumours in immunodeficient mice, and are chemoresistant. The functional and phenotypic heterogeneity of cells within tumors arises from genetic instability, epigenetic alteration, and reversible changes in cell characteristics influenced by the tumor microenvironment.

Identification

Cancer stem cells can be identified by their expression of specific cell surface markers. These markers differ depending on the type of cancer. For example, in leukemia, cancer stem cells can be identified by the cell surface marker CD34+, while in breast cancer, they can be identified by the cell surface marker CD44+CD24-/low.

Role in Cancer Progression

Cancer stem cells are believed to play a crucial role in cancer progression. They are responsible for the initiation, growth, and recurrence of cancer. They are also believed to be the cells that spread cancer (metastasis) from the original tumor to other parts of the body.

Therapeutic Implications

The existence of cancer stem cells has significant therapeutic implications. Traditional cancer treatments, such as chemotherapy and radiation, often do not kill cancer stem cells. This is believed to be one of the reasons why cancer often recurs after treatment. Therefore, new treatments that specifically target cancer stem cells are being developed.

See Also

• Stem cell
• Cancer
• Tumor microenvironment
• Metastasis