Understanding Genetic Testing for Cancer

Cancer is a disease of the genes. Most cancers develop as a result of genetic damage or a mutation that happens sometime during a person’s lifetime. These are called sporadic cancers (occurs by chance). These types of mutations only affect the cells that grow from the original mutated cell. Cancers that result from DNA damage that is passed on is called hereditary cancers. These cancers tend to run in families. They cause hereditary cancer syndromes, but overall are linked to only about 5% to 10% of all cancer cases. Genetic testing can be used to look for the gene changes that are linked to these hereditary cancer syndromes in people thought to be at risk for having one of them.

The risk of developing cancer is higher in people who are born with certain genetic defects that are passed on from their parents and found in every cell in their body. These defects occur in areas of the DNA that affect cell division, cell death, and the repair of damaged DNA.

In most cases, a blood sample is needed to do genetic testing, but sometimes saliva, skin cells, or cells swabbed from the inside of the cheek can be used. The sample is sent to a lab where the actual testing is done. It usually takes a few weeks to get the results.

You will meet with the genetic counselor to go over the results and figure out what they mean for you and your family.

Click here to learn more about genetic testing and the different tests offered.