Reading articles like this reminds me how little we know. Before we had a theory of germs (viruses and bacteria), we believed that sickness came from phlogiston. This did a decent job of explaining how disease spread, but didn't do a very good job of how explaining how it originated. If you were sick, you were enveloped in a cloud of invisible nastiness, and staying away was a good way to remain healthy. Certain things, like carcasses and stinky puddles, were thought to be carriers of phlogiston.

The thing that I find most interesting about the theory of phlogiston is how close it is. It's almost right, but humanity needed a fundamental shift in the way we thought about disease to actually start to solve the problems of disease. I feel like cancer is the modern form of phlogiston. It's close, but cancer is slippery enough that it's got to be wrong; I want to be clear, though, that the theory may still be useful.

Now, perhaps breaking down cancer into it's distinct forms (breast cancer, skin cancer, etc.) will get us there - this approach may have led us to the discovery af germs as different types of phlogiston. But I can't help but think that our mental model for cancer is wrong.