Research by ICEP researchers and collaborators supports a causal role of smoking in the development of breast and colorectal cancer.
The researchers used Genome-Wide Association summary data to identify 126 genetic variants associated with lifetime smoking, and 112 variants associated with ever having smoked regularly. They carried out two-sample Mendelian randomisation to examine these variants in relation to incident breast and colorectal cancer.
There was a positive association with higher lifetime smoking with breast cancer risk and with colorectal cancer. However, ever having smoked regularly was not associated with increased risks of the two cancers.