If a member of your immediate family has had colorectal cancer you are at increased risk of getting the disease. About 75 percent of people with colorectal cancer, however, do not have a close relative with the disease. As with most diseases, both environment and genes play a role.
Colorectal cancer is no exception.
Some family members will inherit genes that predispose them to colon cancer, and others will not. Some family members will be exposed to environmental agents that trigger the disease, and others will not.