Where Did Cancer Come From?
It’s a fairly hard hitting fact, but on average half of us will get cancer at some point in our lives.
To understand how to best tackle this astonishingly pervasive disease, we need to understand where it came from. We might think of cancer as being a relatively modern disease – after all, smoking is the cause of a third of all cancers today – but the history of it goes back much further then you may realize. Hundreds of millions of years, in fact.
Cancer is by no means a new disease. We even have evidence of dinosaurs being afflicted by tumors. One study looked at over 10,000 X-rays of fossilized dinosaur vertebrae from more than 700 different museum specimens. These remains spanned a massive array of species, from the plant-eating stegosaurs to the ferocious tyrannosaurs.
They found evidence of 29 tumors in the fossilized bones of these long extinct beasts. But there was something else even more curious. All of the bones found to contain tumors came from hadrosaurs, also known as the duck-billed dinosaurs, dating to the Cretaceous period around 70 million years ago. Why these dinosaurs seemed to be particularly susceptible is not really understood, and according to the researchers might never be.
Only relatively recently did another group of researchers find a tumor in the fossil of a titanosaur, which is the first evidence to show that cancer was present in a dinosaur that was not a hadrosaur.
Even when it comes to our own lineage the evidence of cancer goes back an impressive distance. The earliest known hominin found to have the disease is a nearly 2-million-year-old benign tumor in the vertebrae of an Australopithecus sediba child. At this point, our ancestors still looked pretty ape-like though probably had a mosaic of features somewhere in between apes and humans.
When it comes to evidence of the first ever malignant tumor in our ancestors, it isn’t that far behind. A toe bone dating to roughly 1.7 million years old, found in South Africa and belonging to an as yet unidentified species of hominin has been diagnosed using its morphology as an osteosarcoma. While all that is known about the individual is the cancerous toe bone, the researchers can be certain that it would have made walking or running extremely painful.
All of this evidence very clearly shows that cancer is not a modern disease, as some like to suggest, or that it is even limited to humans. We know many species living today develop cancer, and the fossil record clearly suggests that many long extinct animals also got the disease, too.
Yet while today cancer is one of the leading causes of deaths worldwide, it is not as common as you might expect in antiquity.
This is mainly to do with the fact that people simply did not live long enough for the disease to manifest itself, and people were most probably dying first of other diseases far less common in the modern world, but also because any cancerous of soft tissue won’t have survived.
The earliest written mention of cancer is thought to be in Ancient Egyptian texts dating to at least 1600 BCE and potentially as old as 2500 BCE, with one even including how to remove a breast tumor by cauterization. Throughout antiquity, cancer was noted and described, with the word being coined by Hippocrates, who referred to tumors as “karkinos”, from the Greek word for crab.
As the oncologist, Siddhartha Mukherjee, and author of the book The Emperor of All Maladies, wrote: “Civilization did not cause cancer, but by extending human lifespans, civilization unveiled it.”
Unfortunately, the dark conclusion seems to be that cancer is likely an inevitability as soon as an organism becomes multicellular. Evolution relies on the fact that the DNA in your cells mutate, creating variation within a population on which natural selection can work. It is this same system that allows cancer to arise, as cells mutate and break free of the checks and controls that normally prevent them from proliferating.
This might sound like there is nothing we can do to prevent it, but that is not really true. When we talk about “cancer” we are effectively referring to hundreds of different diseases. This means that talking about a cure for “cancer” is misleading, and while there are clear difficulties in treating what is, in effect, our own body cells going rogue, we are making some striking advances.