This is the generally accepted story of cancer. A vulnerable cell is exposed to a mutagenic agent—something that causes a change to the cell’s DNA and a mutation in its genetic code. The cell, which until then has been stable with characteristics of the tissue of which it is a part, starts a process of uncontrollable division. The cell regresses to an undifferentiated state so that, looking at the cell in isolation, you would not be able to tell what tissue it came from. Once launched, this process is irreversible. Treatment consists, in essence, of killing this out-of-control cell and its offspring.
This theory is known as the somatic mutation theory of cancer. It has dominated cancer research since the 1950s and has been bolstered by the obsessive research on the human genome.
Here is one of many experiments that the somatic mutation theory can’t explain. Two types of cell were taken from rat mammary glands. One type, the stroma cell, provides structural support for the parenchymal cells that do the actual work of an organ such as the mammary glands. The other type, the epithelial cell, is the cell layer that separates the inside from the outside of an organ such as the milk ducts. The researchers isolated each cell type and exposed half of each kind to a mutagen: half of the stroma cells were exposed, half were not; half of the epithelial cells were exposed, half were not. They then essentially rinsed the exposed cells of the mutagen and combined exposed stroma cells with clean epithelial cells and exposed epithelial cells with clean, unexposed stroma cells.
According to the somatic mutation theory, the exposed cells, whether stroma or epithelial, should have turned into a cancer. Instead, only the stroma cells turned into cancer cells. Exposed epithelial cells combined with unexposed stroma cells did not become cancers. This experiment is not unique in its results.
The journal Nature Reviews recently published an article that describes an alternative referred to as the tissue organization field theory. The tissue organization field theory has been gaining ground over the last two decades, although it has deep roots in developmental and evolutionary biology going back almost a century. In its current form, the theory has developed in response to concerns with our exposure to endocrine disrupting chemicals and the increasing body of evidence linking those exposures to cancer risks.
However, because hormones do not affect DNA but instead are communicators among tissues, their relationship to cancer is a complete puzzle to conventional cancer research. What the tissue organization field theory proposes is that cancer is not about a cell going wild, regressing to a primitive state, and proliferating uncontrollably. Instead, cells are already prone to proliferate and revert to a primitive state. They are kept in check by the communication among tissues. Cancer occurs when that communication breaks down.
This sounds simple, but in fact is not. For example, response to an endocrine disruptor varies dramatically depending on the person’s developmental stage. As adults, exposure disrupts communication among tissues but can be reversed by removing the exposure and compensating for it. But as a fetus, young child, or adolescent whose biology is developing, exposure changes the very organization of tissues permanently. Among other things, this tells us that the origin of a cancer dates years if not decades before its appearance.
The tissue field theory also makes sense of so-called spontaneous remissions of cancer. Last week, the journal Cell published research that reported a comparison of two populations of mice. Both populations were exposed to a carcinogen. One population was provided with an enriched environment: more mouse playtime, more toys, more novelty to their living conditions. Without any other interventions, these mice had smaller tumors. The more time they spent in their enriched environment before the exposure, the smaller the tumors. And whereas all the mice in the standard environment developed tumors, many in the enriched environment did not.
To my mind, this is another demonstration of the tissue field theory at work—environmental change that promotes communication among tissues.
I also believe that the implications go well beyond the obvious actions called for to prevent exposure in the first place. Because the tissue field theory holds that cancer is reversible, it points us toward treatment options that promote the health of tissues not the destruction of out-of-control cells.
There’s more. The authors of the Nature Reviews article point to the role of endocrine disruptors in the rise of many of the chronic illnesses that plague us: cardiovascular disease, diabetes, obesity, multiple chemical sensitivity, and thyroid disorders.
The CDC just published a report on the failure of public health institutions in meeting 2010 targets for obesity that were set in 2000. Not only did they not meet their targets, the situation has gotten worse. Their response? Do more of same: more dietary change (based on the food pyramid, of course) and more physical activity.
What if a bad diet and physical inactivity are symptoms, not causes? What if the problem is a chemical environment that’s been poured on us with no consideration of the consequences? What if we started to look for solutions in the way our tissues talk to each other?