For many people, cancer is a disease. However, for certain scientists and mathematicians, cancer is more than that: it is a small ecosystem inside the body that has interesting connections to the ecology of invasive species. These scientists are actually using modeling of invasive species to further examine the dynamics of cancer spreading.
Picture of a breast cancer cell from a scanning electron microscope, found at: http://commons.wikimedia.org/wiki/File:Breast_cancer_cell_%281%29.jpg
Here’s how it works:
What’s an invasive species?
An invasive species is a species that originates from another area in the world, but is introduced by humans to a different ecosystem, either by accident or on purpose. Invasive species are generalists, meaning they can easily adapt to new environments, they have no natural predators in their new environment, and they spread and reproduce very quickly. Eventually, invasive species take over their new ecosystem, either eating the native species or eating the food of the native species so that the native species can no longer survive.
Invasive species have become such a problem with increasing travel around the world that scientists and mathematicians have been modeling the dynamics of invasive species for a long time. Invasive species are introduced, usually at ports or coasts, and they establish an initial population. Sometimes, there is a lag period between the initial population and when they begin to spread, but eventually the species will venture into new environments and establish new populations in new areas until they have taken over.
How is this similar to cancer?
The dynamics of invasive species have been shown to be similar to metastasizing cancer cells (or cancer cells that spread from one area of the body to another). These cells have similar properties to invasive species: they have to easily adapt to new environments in the body and they spread and reproduce very quickly and they have no natural “predators” in the body. Metastasizing cancer cells originate in one location of the body, set up an initial population, and begin to spread to other regions of the body.
Above is shown the differences between cancer cells and normal cells, found at: http://commons.wikimedia.org/wiki/File:Normal_and_cancer_cells_%28labeled%29_illustration.jpg
So, why is this important?
Modeling cancer cells as similar to invasive species can give scientists further insights into how cancer moves throughout the body. For example, it has been shown that cancer cells stay in their initial population without spreading for a while, very similar to what happens in invasive species. If we can apply our vast understanding of invasive species to cancer, according to the paper we can better model “initial density, metastatic seeding into the bone marrow and growth once the cells are present, and movement of cells out of the bone marrow niche and apoptosis of cells” (Chen and Pienta 2011).
Looking at cancer as a species in an ecosystem could be both an interesting and informative perspective! If you want to know more about this, see the paper (the first link below).