They’ re ba-ack. The scientists who caused a mix 2 years ago— by reporting that DNA copying mistakes could explain most of the differences in cancer risk among various tissues— have expanded their findings. They now tackle a more general question: What fraction of mutations within cancer are due to DNA copying errors, as opposed to hereditary inheritance or lifestyle factors.

The researchers, Cristian Tomasetti, Ph. D., and Bert Vogelstein, M. D., each of Johns Hopkins Kimmel Cancer Center, examined thirty-two cancer types, compared cancer incidence and stem cellular division rates, and estimated that 66% of malignancy mutations result from copying errors. Lifestyle or environmental elements and inherited factors account for 29% and 5% associated with cancer mutations, respectively.

Details of the scientists’ results made an appearance March 24 in the journal Science, in an article titled “ Stem Cell Divisions, Somatic Mutations, Cancer Charge, and Cancer Prevention. ” This article, unlike the one that made an appearance 2 …