Commentary: What can Mendelian randomization tell us about causes of cancer?

Abstract

Multiple important causes of cancer have been successfully identified over the past 70 years, including cigarette smoking, alcohol, obesity and UV light, as well as carcinogens in the occupational environment and different infections. However, despite these successes, about half of the cancer burden cannot be linked to known causes. Difficulties in identifying causal factors for different cancers are due to a number of reasons including limitations in epidemiological study designs and the inherent problems of confounding and reverse causation, as well as inadequate statistical power to study relatively rare cancer types. Potential causes may also be relatively ubiquitous within populations, such as air pollution or water contaminants, and may only be relevant during time windows such as childhood or young adulthood.