Comment on "Variation in cancer risk among tissues can be explained by the number of stem cell divisions"

Tomasetti and Vogelstein (Science 347, 78-81, 2015) claimed that \"primary prevention measures are not likely to be very effective\" for many cancers because they arise mostly from random mutations fixed during stem cell division, independently of specific genetic or environmental factors. We demonstrate that their calculation for hepatocellular carcinomas overlooked a major subset of tumors proven to be preventable through vaccination. The problem, which is not limited to hepatocellular carcinoma, arises from the general reliance of their analysis on average USA incidences and the omission of incidences in specific risk groups.