No, two-thirds of all cancers are not caused by bad luck

I am sure we all read it in the papers several weeks ago: Two-thirds of all cancers are caused by bad luck. The New York Times said so. Science magazine, which published the original article said so too.

Only problem, the original article did not say that, and to her credit, Jennifer Couzin-Frankel, the Science reporter who “said so too,” corrected the record in a sort of meditation on the difficulty of getting difficult scientific concepts correct while working on deadline.

In fact, the authors did not say that “[r]andom mutations may account for two-thirds of the risk of getting many types of cancer, leaving the usual suspects—heredity and environmental factors—to account for only one-third, …” as the Times put it. What they said was more subtle, that two-thirds of the difference in cancer rates between different tissues could be explained by random bad luck. That is, “[s]ome tissues are overtaken by cancer more readily than others, and mutations accumulating in stem cells explained two-thirds of that variability,” in Couzin-Frankel’s words.

It is good to know that Science is self-correcting.