Genetics & cancer risks

Cancer is a disease of the genes, caused when DNA damage becomes fixed in the cells of our body. Anyone can develop cancer as they age and genetic damage builds up in cells, but the genes a person inherits, their lifestyle and their environment all contribute to their risk.

Research aims to unravel the roles played by genes, behaviour and environmental exposures in the development of cancer, as a means of finding ways to identify people most at risk of cancer and helping them manage their risk. Understanding the causes of cancer can also provide important clues about how to treat it.

Some people inherit a particularly high risk of developing certain cancers. Around 5–10% of women with breast cancer, for instance, have inherited specific genetic mutations raising their risk of developing the disease. Scientists work on identifying both rare gene mutations that substantially increase the risk of cancer and much more common genetic variants that individually only have a small effect on risk. They have identified a large number of genetic risk factors for a wide variety of cancers, including breast, ovarian, prostate, lung, testicular, brain, haematological and childhood cancers.

Several long-term studies following large numbers of people over time are being conducted in order to explore how genetic, behavioural and environmental factors may together affect cancer risk. For example, the ICR hosts the Breakthrough Generations Study – funded by Breast Cancer Now – which is starting to unpick how lifestyle, and factors such as the age at which women hit puberty or the menopause, play a role in the development of breast cancer.

An understanding of the genetic, behavioural and environmental causes of cancer can help in finding new ways of detecting, managing or preventing cancers, and provide important clues about how cancer develops.