October 7th, 2019

After finishing the talk on Autoimmunity and the environment last Thursday, I read about a lovely new theory on cancer. It is believed that we are exposed to cancer inducing environments not too infrequently meaning that we all develop cancer cells more often than we think. In a fascinating new article in the August edition of the Journal Scientific American, Drs. DeGregori and Gatenby take us on a new theory journey of cancer and it's treatment.

They liken the cancer biology to be akin to Darwin's natural selection theory with survival of the fittest reigning supreme. Thinking outside of the box has often been the route to new ideas, treatments and cures in medicine.

These two men are no different as displayed in this article. "If you asked any doctor or cancer researcher, "why is aging, smoking or radiation exposure associated with cancer?" you will probably get a short answer: "these things cause mutations." They go on to note that this answer is only partially correct as the mutation is neither advantageous or disadvantageous to the cell until we know the environment that it exists in.

They use a parallel analogy of Darwin's Galapagos Finches which are birds with slightly different beak shape and survival patterns on different islands. A long beak versus a short beak may help or hinder the bird's ability to find food in their local environment. If the long beak proves more useful to finding food, then natural selection says that this bird will grow and procreate faster than the short beak variety. However, if a sudden environmental change occurs and the insects that were hidden requiring the long beak are now dead, then the short beaked bird will have a new equal or even possibly enhanced selection pressure.

They have applied this theory to cancer cells. If we treat a cancer cell with chemotherapy that is highly destructive to the cancer cell as well as our cells, then natural selection would hold that the most adaptive cells, cancer or not,will survive. This has been a dysfunctional problem for oncologists as the toxicity of the cancer treatment is not good for our good native cells, but also the cancer cells that do not die are clearly very adaptive and thus selected to survive. The end result is a regrowth of the cancer with hardier cells that evade our chemotherapy and kill the host more rapidly now.

They propose and are actively testing a more adaptive therapy that allows the cancer cells to be killed to an extent but not aggressively. The lack of therapeutic aggression takes away the selective pressure that allows the more robust chemo-resistant cells to flourish. The end result is a slowly growing cancer mass that waxes and wanes with the more mild therapy. It is as if you plan to live with the cancer in its mild form without damage to you. Not a bad theory.

This theory has serious merit as I see similar theories playing out in the microbiome of humans and mammals alike. Heavy antibiotic use selects for highly specialized bacteria to thrive at the expense of their weaker less adapted brethren leaving the environment less diverse and consequently less functional.

When it comes to understanding cancer in general, we need to understand that the cellular environments inherent to our actions raise or lower the risk of disease. Aging, toxin exposure, poor nutrient intake, stress and many other lifestyle factors can promote intracellular environments that are cancer promoting.

For example, excess sugar intake drives inflammation and a negative reaction on AMPkinase and secondarily myeloid derived suppressor cells reducing natural killer cell numbers directly reducing the surveillance and killing of rouge cancer cells. It is no wonder that obesity is a major risk factor for cancer.

The bottom line to all of this is simple: aim for a balanced lifestyle that promotes a healthy surveillance immune system and killing capacity that allows Darwinian selection to keep you around for a long time!

Dr. M