Cancer engineers its own ecosystem.
As soon as cancer cells begin to form a tumor, long before clinical detection, cancer initiates ecosystem engineering that modifies the native healthy ecosystem of the host organ, ultimately resulting in ecosystem collapse and the generation of a “cancer swamp.”
If we can understand how these conditions are generated and the impact of
the changing ecosystem, we can begin to understand the initiating events
of lethal cancer.
One of the most recognizable examples of ecosystem collapse is cultural eutrophication and its characteristic algal bloom. Polluted runoff stimulates the growth of photosynthetic algae. As the algae die off, decomposition levels increase, leading to severe hypoxia. Only anaerobic decomposers survive and thrive in this ecosystem, and the buildup of their waste products results in an acidic environment. If left unchecked, native species will go extinct and the ecosystem will irreversibly collapse.
In an analogous process, a tumor undergoes a process of autoeutrophication which is initiated and driven by the cancer cells themselves. As the cancer cells proliferate, the tumor rapidly grows and outstrips it’s available vasculature, representing both its source of nutrients and source of waste displacement. Therefore, the tumor rapidly exhausts the local nutrient and oxygen sources while simultaneous pinioning the habitat. Under the hypoxic conditions, cancer cells change how they produce energy, resulting in an accumulation of lactic acid and resulting in a metabolite-poor habitat. Ultimately, this highly hypoxic, acidic, and nutrient poor “cancer swamp” both applies adaptive stress to the surviving cells, results in extinction of native host cell species, and results in irreversible ecosystem collapse.