Genetic Testing in Pancreatic Cancer

The actual cause of pancreatic cancer is not known but is thought to be a result of a combination of inherited genetic changes and genetic changes caused by environmental exposures. While most cases of pancreatic cancer are considered “sporadic” or not inherited, about 10% are considered hereditary (passed down from generation to generation) or familial (seen in families with multiple cases of pancreatic cancer).

If you or a close family member have been diagnosed with “exocrine” pancreatic cancer, you may be offered genetic testing. Exocrine pancreatic cancer may also be called adenocarcinoma or just “pancreatic cancer.” This is different than a neuroendocrine tumor (NET) in the pancreas.

How do genetic changes occur?

Genetic changes can happen in two ways:

• A mutated (changed) gene can be passed down, or inherited, from parent to child (called a germline mutation). Germline mutations are present in every cell in your body. Certain mutations can raise a person’s risk of pancreatic cancer. About 10% of all pancreatic cancers are related to a germline mutation.
• Genes can also be changed or damaged over the course of a person’s life, often due to environmental exposures such as smoking, or health conditions such as diabetes. Sometimes these mutated genes are present only in the cancer cells and can control tumor growth.

When you have genetic testing, the test is looking for a germline mutation. In some cancers, the tumor is tested for specific mutated genes because there are medications available to “target” those mutations. This article will focus on genetic testing for germline mutations.

Who should have genetic testing related to pancreatic cancer?

Guidelines published by the National Comprehensive Cancer Network state that anyone diagnosed with exocrine pancreatic cancer should have genetic counseling and testing. If this test result finds a genetic mutation, relatives may also be tested for the mutation. If the person with pancreatic cancer cannot be tested, first-degree relatives (parents, siblings, children) may still be tested. In some cases, people with second-degree relatives (grandparents, aunts/uncles, nieces/nephews) with pancreatic cancer may be eligible for testing.

To have testing, you should be referred to a genetic counselor. The genetic counselor will talk with you about your family’s history, what tests are available, how testing for genetic mutations is done, and what those results might mean for you and your family. They can also help you understand the test results once you receive them.

What genes are linked to an increased risk of pancreatic cancer?

There are several gene mutations associated with a higher risk of pancreatic cancer. Some are also associated with other types of cancers. It is important to note that studies have found that even with no family history of pancreatic cancer, a person with pancreatic cancer may be found to have a genetic mutation. Below are the genes currently being tested for and the associated cancers or cancer syndromes.

How will genetic testing help me or my family?

If you and your care team decide to do genetics testing, the results could help find similar genetic mutations in family members. Remember, if a mutation is found, it does not mean you will develop cancer. Likewise, if a genetic mutation is not found, it may mean that the specific gene has not been found yet by researchers.

If you have pancreatic cancer, genetics testing can sometimes help guide treatment options. If family members are tested and found to have genetic mutations, research studies are being done to screen these family members for pancreatic cancer. The studies aim to find any cancers in these people early when treatments are most successful. The age at which screening is started depends on the genetic mutation that was found and the age at which the relative was diagnosed with pancreatic cancer.

Researchers have learned a lot about the genetics of pancreatic cancer in the past 5-10 years. This knowledge will continue to grow. If your family or personal history includes pancreatic cancer, meeting with a genetic counselor can help you better understand the options available to you and your family.