Specifically, about 2/3. Another 5% or so are due to inherited mutations, and the rest may be due to lifestyle choices or environmental factors.
We usually attribute cancer to inherited genes such as the BRACA1 or BRACA2 mutations, responsible for breast, ovarian, and prostate cancer. Or else, a lifestyle choice like smoking or something to do with the environment, say exposure to pollution or radiation. A new study published in the journal Science however, makes a strong case for random chance as the biggest driver.
The vast majority of cancers are just a mistake, an error in DNA replication, researchers say. In this way, developing cancer in many cases is unavoidable. Geneticist Bert Vogelstein and mathematician Cristian Tomasetti, at the Johns Hopkins Kimmel Cancer Center, conducted the study, a follow-up to an earlier one, which arrived at the same conclusion.
Of course, some people took issue with this:
Vogelstein and Tomasetti set off a firestorm of debate when they released similar results two years ago. One problem, critics argue, is that these findings dishearten patients. Why should they pursue a healthy lifestyle if they might get cancer anyway?
Well, actually, this doesn't even cover heart disease, emphysema and so on. Still plenty of reasons to "pursue a healthy lifestyle". Besides, this puts the cart before the horse. Science is about the pursuit of truth, not the pursuit of something to motivate people or something to make people feel good or "empowered".