Environmental and Heritable Factors in the Causation of Cancer 

Analyses of Cohorts of Twins from  Sweden, Denmark, and Finland  

The New England Journal of Medicine -- July 13, 2000 -- Vol. 343, No. 2

Paul Lichtenstein, Niels V. Holm, Pia K. Verkasalo, Anastasia Iliadou, Jaakko Kaprio, Markku Koskenvuo, Eero Pukkala, Axel Skytthe, Kari Hemminki

Abstract

Background. The contribution of hereditary factors to the causation of sporadic cancer is unclear. Studies of twins make it possible to estimate the overall contribution of inherited genes to the development of malignant diseases.

Methods. We combined data on 44,788 pairs of twins listed in the Swedish, Danish, and Finnish twin registries in order to assess the risks of cancer at 28 anatomical sites for the twins of persons with cancer. Statistical modeling was used to estimate the relative importance of heritable and environmental factors in causing cancer at 11 of those sites.

Results. At least one cancer occurred in 10,803 persons among 9512 pairs of twins. An increased risk was found among the twins of affected persons for stomach, colorectal, lung, breast, and prostate cancer. Statistically significant effects of heritable factors were observed for prostate cancer (42 percent of the risk may be explained by heritable factors; 95 percent confidence interval, 29 to 50 percent), colorectal cancer (35 percent; 95 percent confidence interval, 10 to 48 percent), and breast cancer (27 percent; 95 percent confidence interval, 4 to 41 percent).

Conclusions. Inherited genetic factors make a minor contribution to susceptibility to most types of neoplasms. This finding indicates that the environment has the principal role in causing sporadic cancer. The relatively large effect of heritability in cancer at a few sites (such as prostate and colorectal cancer) suggests major gaps in our knowledge of the genetics of cancer. (N Engl J Med 2000;343:78-85.)

 

Source Information

From the Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden (P.L., A.I.); the Institute of Public Health (Epidemiology) and the Danish Twin Registry, University of Southern Denmark, Odense (N.V.H., A.S.); the Department of Public Health, University of Helsinki, Helsinki, Finland (P.K.V., J.K., M.K.); the Department of Public Health and General Practice, University of Oulu, Oulu, Finland (J.K.); the Department of Public Health, University of Turku, Turku, Finland (M.K.); the Finnish Cancer Registry, Helsinki, Finland (E.P.); and the Department of Biosciences at Novum, Karolinska Institute, Stockholm, Sweden (K.H.). Address reprint requests to Dr. Lichtenstein at the Department of Medical Epidemiology, Karolinska Institute, Box 281, SE-171 77 Stockholm, Sweden, or at paul.lichtenstein@mep.ki.se.

page source: http://www.nejm.org/content/2000/0343/0002/0078.asp  downloaded 14 Apr 2005