I think it is possible that we might all have cancer.
Yes, even you who are reading this column right now.
Usually we wonder why someone gets cancer. This is especially true when that someone happens to be you, which was the case for me in late 2009 when I was diagnosed with apparently aggressive prostate cancer at age 42. I never thought cancer would happen to me or at least never at such a young age, but there I was out of the blue: a cancer patient.
Why me? Why does anyone get cancer?
Good questions but with few answers.
Now as a cancer biologist I also have started to wonder about another question that is more counterintuitive:
Why don't all people get cancer all the time?
Now, I have come to suspect that maybe everyone does get cancer and most or all of us have it this very moment, but just don’t know it.
You see, our cells make a lot of mistakes as they go about their lives and many of these mistakes tend to make the cells more like cancer.
Luckily, cells are very prone to committing cellular suicide (aka apoptosis) if they sense anything is wrong, which is a major way we escape from many cancers.
But a particularly nasty combo is when the cellular mistake is a mutation in the pathway by which cells commit suicide.
With that mutation, then the cell either does not “know” it is damaged so it goes on its merry way or even if it senses something is wrong it cannot kill itself, in either case one giant step closer to being cancer.
Other bad cancer-promoting mutations are in genes that correct DNA mistakes, which you can imagine exponentially makes the situation worse. It is kind of like breaking the eraser off of our pencil, but being required to continue writing copying billions of letters.
If you think about the course of human history and evolution, that’s a lot of time for these kinds of cancer-related mutations to accumulate. You might say it is also a long time for humans to evolve away from mutations that might pre-dispose us to cancer since those mutations are "bad", but this does not seem to happen in reality. For you see, most cancers show up clinically speaking after humans have already reproduced and passed on their genes so the majority of cancer-related mutations evade being flushed down the evolutionary toilet.
Another kind of evolution and natural selection occurs not outside, but in our bodies that is very much pro-cancer as well.
As we develop during embryogenesis and childhood and even later in life simply as we live or especially if we are sick or injured, our trillions of cells have to be replaced so there are stem and progenitors that are constantly dividing to fulfill this need.
One cell becomes two, two becomes four, and pretty soon you have millions of cells that are all derived from one stem cell. Along the way, mistakes are inevitable and it is unfortunate that essentially all mistakes that tend to make a cell more prone to become cancer give this cell an evolutionary advantage over its neighbors. You can also imagine the danger if a stem cell happens to be the one that gets mutated and passes that mutation along to millions of progeny.
We do not think about it, but the reality is that cells compete with each other inside of us. There is a kind of micro version of "survival of the fittest" and natural section going on inside of us as though we were mini-Earths....and the winners are pre-cancerous cells. These pre-cancerous cells on a potential path to become full-blown cancer are the winners of the evolutionary race inside of us because they grow faster, are less likely to die, and avoid differentiation far more than their normal neighbors.
What this means is that an axiom of cell biology is that the more cancer-like a cell is, the more that cell will tend to have its offspring cells over-represented in our bodies over time, which is of course a very bad thing.
So why don’t we get clinically apparent cancer even more often?
Scientists do not really know. One possibility is that our immune systems are far better at finding and destroying cancer than we ever imagined. Indeed, from this perspective cancer may frequently be an immune disorder more than anything.
The other more frightening answer to the "why?" questions about cancer that I alluded to earlier requires thinking out of the box, arguing that in fact we do all get cancer and maybe almost all of us adults have cancer cells in us right this moment. But the cancers poop out or are killed by our immune systems on a regular basis or most often differentiate and stop proliferating. They are cancer cells but they do not become clinically evident cancer most of the time.
If this is true that we as adults all have cancer, then a key next question is why only some of us manifest it clinically and then only an additional subset die of it?
If only we knew the answer to those kinds of questions, but 4 decades into the “war on cancer” we still know very few answers to the most critical questions and generally have not made much clinically relevant progress overall against cancer...so perhaps it is well past time to start thinking outside of the box about cancer and asking surprising questions and challenging the dogma out there.