The War on Cancer Part Two: The Biology of Cancer
Nov 27, 2019 07:30AM
by Laura Weis
If you know the enemy and know yourself, you need not fear the result of a hundred battles… If you know neither the enemy nor yourself, you will succumb in every battle.
~Sun Tzu, The Art of War
In the first of this three-part series, we examined the failing war on cancer, the history of cancer therapies and current approaches, and why we have not made progress in reducing cancer rates and deaths in humans and animals. Now it is time to dig into some biochemistry and evolutionary biology to understand the biology of cancer, which was written into our genes when life was just beginning. The elegant compromises and adaptations for producing cellular energy that led to the development of all multicellular life forms from early single-celled organisms also gave rise to the potential for unchecked cell growth that we call cancer.
The earliest single-celled organisms developed two methods for producing energy in the universal currency of ATP. When food was abundant, a more primitive and inefficient method called fermentation, or glycolysis, could be used. For times of scarcity, cells developed a more efficient means of producing energy, through membrane-embedded complex electron chains that eventually were able to use oxygen as final electron receptors. This more efficient process is called aerobic respiration, or oxidative phosphorylation. Fermentation is a much older process and has been in use since life started about four billion years ago. The key features of primitive life were constant reproduction and constant mutation.
Around two billion years ago one of the most fascinating parts of the cancer story occurred. A type of single-celled bacteria invaded another form of single-celled life called Archaea, and the two developed a mutually beneficial relationship. The bacteria primarily used respiration to produce energy, while the Archaea relied on fermentation. In this ancient compromise, the bacteria agreed to exchange energy production for shelter and food provided by the invaded host cells. Over the next billion years, the bacteria transformed into the mitochondria that are the energy-producing powers of modern organisms, and in the process transferred most of their genes into the developing nuclei of the cells, which are well-protected from disrupting carcinogens such as radiation and chemicals. Eventually, the mitochondria became the decision-makers for growth and reproduction in our differentiated modern cells. In times of scarcity, not only do our mitochondria efficiently produce energy, they also signal genes in the nucleus to shut down growth and reproduction.
Unfortunately, this complex energy production system left us vulnerable to the possibility of cancer. The genes in the nuclei of our cells are highly protected; the 37 genes that comprise the mitochondrial genome and reside in the cellular cytoplasm are highly vulnerable to damage from carcinogens and mutagens. Instructions from the mitochondria are responsible for turning on and off pathways that are necessary for the formation of tumors, including major growth-suppressor genes, genes that cause damaged and old cells to commit suicide, genes that promote the development of blood vessels, genes that maintain the cell in a well-differentiated state and genes that lead to the metastasis of tumors.
Eventually when cellular processes go awry, additional individual mutations develop in the nuclear genome. It is these end-stage mutations that some of the cutting-edge cancer therapies target in a misguided attempt that mistakes outcome for causation. We know this to be true from research on “cybrids”, cells constructed using parts from two or more cells. When the nucleus from a healthy cell with healthy cytoplasm containing healthy mitochondria is replaced with the nucleus from a cancer cell, no cancer develops. When the nucleus from a cancer cell is replaced with the nucleus from a healthy cell, the cell remains cancerous. The diseased mitochondria are directing the process. The theory of cancer as a collection of individual mutations of nuclear genetic material is incorrect.
This complex topic can be explored in detail in the book Cancer as a Metabolic Disease by Thomas Seyfried, as well as in numerous other articles. Fortunately, “knowing the enemy and knowing ourselves” is really one and the same. It is this knowledge that can lead to a unified approach to cancer prevention and therapy, outlined in the final article in this series.
Dr. Laura Weis and her husband, Dr. Ransome Weis, own and operate Doylestown Veterinary Hospital & Holistic Pet Care, and Holiday House Pet Resort & Training Center, in Doylestown. She focuses on homeopathy and nutrition counseling for her clients within the full-service veterinary practice. Call 215-345-6000 to request an appointment.