Vogelstein, who is also an investigator with the Howard Hughes Medical Institute, explained how he and Tomasetti have refined that question. He notes that every time a perfectly normal cell divides, it makes several mistakes when it copies its DNA. These are naturally occurring mutations.The study is behind a paywall. The journal has this editorial comment:
Most of the time, those mutations are in unimportant bits of DNA. That's good luck. "But occasionally they occur in a cancer driver gene. That's bad luck," Vogelstein says.
After two or three of these driver genes get mutated in the same cell, they can transform that healthy cell into a cancer cell.
In their new paper in Science, the researchers set out to quantify how often those random errors are an inevitable part of cell division, how often they're caused by nasty chemicals like tobacco smoke and how often they're inherited.
The answer: 66 percent of the total mutations are random, about 29 percent are due to the environment and the remaining five percent are due to heredity.
These numbers vary depending on the type of cancer, they found.
Lung cancer is largely the result of environmental causes, while the vast majority of childhood cancer is a result of these bad-luck mutations, they found.
It is a human trait to search for explanations for catastrophic events and rule out mere “chance” or “bad luck.” When it comes to human cancer, the issue of natural causes versus bad luck was raised by Tomasetti and Vogelstein about 2 years ago (1). Their study, which was widely misinterpreted as saying that most cancers are due neither to genetic inheritance nor environmental factors but simply bad luck, sparked controversy. To date, a few hundred papers have been written in response, including (2–6), with some [e.g., (2)] coming to opposite conclusions. What is this controversy about? Tomasetti and Vogelstein concluded that 65% of the differences in the risk of certain cancers is linked to stem cell divisions in the various cancerous tissues examined (1). On page 1330 of this issue, Tomasetti et al. (7) provide further evidence that this is not specific to the United States.The research is interesting, but I question whether it makes any sense to say that something is "caused by luck".
What percentage of coin tosses are caused by classical mechanics, and what by luck?
What percentage of car accidents are caused by bad luck?
A lot of researchers have dropped the word "accident" just because of the dubious implication that no one is at fault, or that bad luck is the cause, or that nothing could have been done to prevent it.
Luck is usually a euphemism for unknown cause.
Here, luck is a euphemism for quantum mechanics. The researchers are trying to say that most cancers are caused by quantum mechanics. That sounds silly because quantum mechanics is the cause of all chemical reactions, so one could say that on the atomic level, quantum mechanics explains all cancers and biochemical processes and everything else.
There is a belief that quantum mechanics is grounded in some underlying quantum weirdness that will never be understood by humans. That quantum weirdness is causing the mutations, and hence the cancers. Other cancers can be understood at some higher level, such as cigarette smoking causing lung cancer.
In other words, we say the cell-division mutation cancers are caused by bad luck because they are caused by a quantum weirdness that will never be understood.