NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,800 terms related to cancer and medicine.
Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.
- listen (EH-pih-jeh-NEH-tix)
The study of how age and exposure to environmental factors, such as diet, exercise, drugs, and chemicals, may cause changes in the way genes are switched on and off without changing the actual DNA sequence. These changes can affect a person’s risk of disease and may be passed from parents to their children.