SHARING EXPERTISE
3
QUESTIONS FOR GENETIC COUNSELOR JASON SHANDLER
Jason Shandler is a genetic counselor at the Upstate Cancer Center.
1
What’s the difference between somatic mutations and germline mutations?
All cancer is genetic in the sense that it is caused by mutations in genes, which result in cells growing out of control. However, those mutations can either be acquired during your lifetime or inherited from your mother or father. If it is the latter, there is a risk to pass the mutation on to your children. When we perform genetic testing on tumor cells, the test is determining the presence or absence of an acquired mutation, which is a change identified only in that cancer cell. This testing, also known as somatic testing, is often done to guide treatment options; perhaps a specific treatment or drug has been developed that can target the specific mutation found in the patient’s tumor cells. A somatic mutation may arise due to an exposure or a mistake during replication of the genetic information, but it is unlikely to be present in other tissues, such as an egg or sperm. Mutations present in all of your cells, including egg or sperm, are
12
C A N C E R C A R E l spring 2022 l upstate.edu/cancer
considered germline mutations. If a mutation is first identified on somatic testing, we must then conduct germline testing to determine if the mutation is present in all of your cells or just in the tumor cells. If the mutation is present in other tissues, it would be considered a germline mutation, and these may be passed on to the next generation. It is important to make the distinction between a mutation that was acquired (somatic) or inherited (germline) for the purposes of treatment decisions and future cancer screenings in that patient and other family members. Identification of a somatic mutation is one reason someone with cancer may seek care from a genetic counselor for hereditary testing.
2
What are the risks of having a germline mutation?
Many of the germline mutations we identify do influence cancer risk. However, each mutation has a different overall risk. Some genes are on the lower end of the risk spectrum, and we are learning a great deal about these as more research is conducted. Other
