While we have not yet cured cancer, we have amassed a great amount of knowledge of about how cancerous tumors operate. Hopefully, these new insights will lead to treatments in the future.
One very interesting finding is that tumors have stem cells just like normal human organs. Previously, we believed that cancer cells were all basically the same- cells growing out of control. We believed that any of these cells would be capable of producing a tumor when implanted into a compatible tissue. In the last decade, this idea has shifted and most scientists agree that there are “stem” cancer cells and “trans-differentiated” cancer cells.
To explore this idea, it’s important to understand stem and trans-differentiated cells in normal tissues. Stem cells are unspecialized cells that have the ability to develop into any type of cell. These stem cells divide and produce new cells, which differentiate from the stem cell-like state. Each successive division leads to a more differentiated cell until it becomes a trans-differentiated cell with a specific function. These trans-differentiated cells cannot reverse their fate and produce other cell types. Unlike immortal stem cells, once a cell trans-differentiates it’s life span is limited.
The idea that cancerous tumors have both stem cells and trans-differentiated cells is important when considering treatments. We know that the cells we really want to target with treatments are the cancer stem cells because only these cells are capable of producing new tumors. The trans-differentiated cells, which make up the bulk of a tumor, do not necessarily have to be removed or killed because they will eventually die on their own. This critical realization can help provide better and more direct treatments in the future.
The greatest improvements in curing cancer will likely come from personalized medicine. We now have the technology to identify specific genetic aberrations involved in an individual’s cancer. We are in the early stages of using this technology to determine exactly which drugs can help and whether chemotherapy or radiation is necessary to prevent metastasis.
In the future, it may be possible to identify the specific subtype of cancer affecting an individual, prescribe a drug to treat it, then monitor the cancer’s adaptation to the drug and prescribe a different drug if the cancer becomes drug resistant. Of course, this type of treatment will likely be very expensive (perhaps millions of dollars per person) and we may be faced with moral dilemmas deciding how much money we’re willing to spend to treat cancer.
After the 40-year war on cancer, victory is still not in sight. Great strides have been made in our knowledge of the disease, but treatments have been slower to come. We never know when a ground-breaking discovery could emerge to overcome the disease, but for now we will have to keep searching and making small advances in our knowledge.