One way of looking at it is by examining the mechanisms by which cancer stem cells metastasize. This is the process by which a single cell travels from a primary tumour to a distant site, re-creating the tumour’s complex architecture. One way to look at cancer stem cells is through the lens of the cancer stem cell hypothesis. The orthodox model of cancer stem cells assumes that a tumour contains all of these stem-like cells. However, recent studies have suggested that tumours are characterized by a gene known as ALDH, which is highly expressed in neural and blood-forming stem cells. This gene expression was also associated with a shorter life span.
Another way to define cancer stem cells is by their ability to generate more SCs, while also generating differentiated cells. CSCs accomplish both tasks through asymmetric cell division. One progeny of this type of cell maintains its SC identity while the other undergoes several rounds of post-mitotic differentiation. However, there is no consensus among researchers regarding the classification of cancer stem cells. This complicates efforts to target tumor stem cells and to determine where they originate.
Researchers hope to find ways to identify cancer stem cells so that they can treat cancer. They hope that by understanding the role of healthy stem cells, they can better identify cancer stem cells. In fact, John Dick first discovered leukaemia stem cells. Since then, assays for blood-forming stem cells were well developed, this discovery could prove beneficial in the field of cancer research. And if a cancer stem cell is successful, it could lead to a new way to treat cancer.
The research on cancer stem cells has uncovered two distinct types of cancer stem cells. One type is a cancer-stem cell with origins in an organ-specific adult stem cell. This type expresses the Oct4A gene and lacks functional gap junctional intercellular communication. The other type does not have this gene and is thus known as an iPS cell. This suggests that cancer stem cells are both cancer-causing and benign.
One possible mechanism that cancer stem cells use to avoid the apoptosis phenotype is the blockage of DNA repair. Those cancer stem cells can also be resistant to anti-cancer drugs. This resistance may be due to the presence of quiescent cancer stem cells in their body. However, these cells are still capable of regaining their stemness when treated with chemotherapy drugs. In addition to the resistance to chemotherapy drugs, some cancer stem cells can also be resistant to drugs that block the ability of cells to undergo apoptosis.
These stem cells also have a role in organ regeneration. Inflammation or tissue injury can result in a tumor’s stem cells to reproduce. Inflammatory proteins in the body can interfere with cancer stem cell division. Ultimately, this can result in a tumour regrowth. The diseased cancer stem cell is often the product of a mutation in a gene that controls tumor growth. It is therefore important to identify any mutations in cancer stem cells and treat them accordingly.
