Darwin’s Paradox

IndieInk, Research, Science, Whatnot Comments (7)

This week’s installment of the IndieInk Writing Challenge was submitted by Wendryn:

It supplements a week that’s been jam packed with science-related blah blah. My challenge this week fell to Zee, whose response can be found here.

The world of biomedical research affords a person countless ways to be humbled. Years spent wallowing in molecular biology and biochemistry and have granted me an understanding of how humans work that I’d never previously considered possible. At times, however, such knowledge can be equal parts comforting and disconcerting. Mostly I simply try to avoid being overwhelmed by the realization of how many things have to happen perfectly at the molecular level after every blink in order for us to not fall over dead.

We survive because we evolve. Our immune system learns over the course of our existence and adapts into something remarkably efficient at keeping us alive. This is also why it’s dysfunction is so potentially devastating. Autoimmune diseases like lupus occur when our immune system stops recognizing its host as a ‘good guy’ and begins attacking the organism it’s supposed to protect, loyalty be damned. Autoimmunity involves a significant part of my research. It’s complicated and fascinating and heartbreaking in the way that the most interesting relationships tend to be. It’s also why I respect cancer.

We are literally full of cells. In order to maintain a healthy equilibrium, an absurd amount of them die daily, replaced at an ~equal rate with identical cells. The process of living and dying is tightly regulated, overseen by specific cellular machinery and to a certain degree by the immune system. Each of these cells contains a copy of your genome, which is basically your blueprint. Now let’s say something happens to a gene, a mutation of some sort caused by eating paint chips or drinking diet coke. That mutation alters the regulation of the cell cycle in such a way that instead of dying, that cell just keeps dividing. Each cycle of cell division results in copies of the genome with that same mutation, so the number of defective cells starts to proliferate.

Sometimes these things can be fixed. There are internal repair pathways that might be able find the mutation and fix it. There are also ‘signals’ that can cause the cell to alter its machinery in ways to offset the effects of the mutation. Then there are proverbial ‘red flags’ that the cell can start ‘waving’ to signal the immune system that something’s wrong. What makes cancer so lethal is that over time, these mutated cells adapt to these efforts and find ways to overcome them. They may mutate other parts of the genome to suppress DNA repair mechanisms or perhaps ‘burn’ all the ‘red flags’ so that the immune system hasn’t a clue. Uncontrollable proliferation of these cells results in masses of cancerous tissue called tumors, which have the ability to develop their own vascularization (blood vessel system) that both keeps them ‘fed’ and provides routes through which cancerous cells can migrate elsewhere. Cancer, therefore, prolongs its survival by exploiting processes we normally utilize to heal ourselves. It is, in these and other ways, an evil genius.

Cancer has killed members of my family and very likely yours, as well, with an efficiency rivaled only by the ways in which a functional immune system keeps us alive. There are reasons one should be frightened of viruses, which have their own highly-effective evolutionary cycles that continue to keep humanity on its toes. The complicating factor with cancer is that it survives because it evolves and it evolves because we do. It’s survival is dependent upon our subscribing to Darwinian principles: We learn, adapt, overcome. We builds roads, travel, put down roots, start families. Cancer is human in its ability to persevere because we share the same genome.

Sir @ April 21, 2011