What is the difference between inherited and acquired gene changes?

Cancer is caused by gene changes, but they come in two kinds. According to the National Cancer Institute, inherited changes, also called germline changes, are present in every cell of the body from birth and can be passed from a parent to a child.

Acquired changes, also called somatic changes, happen during a person's life. They can come from random errors as cells divide, from aging, or from carcinogens such as tobacco smoke or UV rays. They are found only in the cells where they occurred, including tumor cells, and are not passed to children.

The vast majority of cancers come from acquired changes that build up over time; up to 10 percent are linked to inherited changes. The difference matters because inherited changes are found with a blood or saliva test, while acquired changes are found by testing the tumor.