Nordic Twin Study of Cancer (NorTwinCan)

The Nordic Twin Study of Cancer (NorTwinCan), launched in 2008 and funded largely by the Ellison Foundation, is the largest twin study in the world available for the research of the heritability and familial risk of cancers such as prostate, breast, ovarian, and colon cancer.

This one-of-a-kind database is comprised of nationwide Nordic Twin Registries from Denmark, Sweden, Finland, and Norway and, remarkably, includes over 300,000 twins with data linked on cancer incidence and mortality over and average of five decades of follow-up.

Equally important is the comprehensive, multi-disciplinary team that disentangles the relative importance of environment versus genetic factors and related information relative to specific cancers. This group is comprised of prominent researchers and biostatisticians from the Harvard School of Public Health (led by Dr. Lorelei Mucci and Dr. Hans-Olov Adami), and National Twin Registries and academic institutions in the four Nordic countries that are involved.

In 2000, Paul Lichtenstein published “Environment and Heritable Factors in the Causation of Cancer – Analyses of Cohorts of Twins from Sweden, Denmark, and Finland,” in the New England Journal of Medicine, which has been cited in peer-reviewed literature more than 1200 times.  Among other goals, this collaboration seeks to expand on that paper with an added registry (Norway) and a decade more of follow-up. This added data allows the researchers to analyze rare cancers, and when paired with the newly developed statistical methods, it gives more power and strength to the estimations of heritability.

For more information, please contact the Program Manager, David Havelick (