Cancer — Nature, Nurture, or Both.

The article cites a study on the relative role of genetic constitution and environmental exposure in the causation of cancer. The study supports the pre-accepted estimate that 80 to 90 percent of human cancer is due to environmental factors. The gold standard for distinguishing genetic from environmental traits has been the study of twins. The present study has several advantages over previous studies of cancer in twins. The study included more than 10,000 cancers in a total population of nearly 90,000 twins in Scandinavia. The study lacks information on screening practices. The study reaches to the conclusion that for cancer at the common sites in monozygotic twins, the rate of concordance is generally less than 15 percent.