Genetics is a word you hear often in the cancer community these days. Below, hear from Gillian Hooker, Genetic Counselor and Director of Clinical Development at NextGxDx, to learn the difference between the genetics of your cancer and the genetics of you and how genetics can guide your treatment plan.
The types of tests doctors use to learn about your cancer and ways to treat it are changing and brining new genetic technologies into the clinic. Researchers are learning more and more about how genes contribute to cancer and using this knowledge to help doctors and patients make better decisions about cancer care. Most genetic tests for cancer fall into one of two categories: 1. Tests that tell you about your cancer 2. Tests that tell you about you
1.The Genetics of Your Cancer
Cancer happens when a single cell in your body has “typos” (mutations) in its DNA that allow it to grow in a way it shouldn’t.
You might imagine that your genes are like the instructions to make the pieces of a car. If you had a typo in a gene that was supposed to make the brakes, you might make a car that can’t stop. Or if you had a typo that made the accelerator stay on all the time, you might also make a car that can’t stop.
These are the kinds of typos that genetic tests directed at your cancer are trying to find. Once the typos are found, in many cases, specific drugs can be used to treat those specific types of cancer. This is likely how cancer will continue to be treated in the future Rather than defining cancer just by the place in the body where it happens, we can now find more precise ways to classify cancers and treat based on the underlying genetic changes.
Common “genetics of cancer” tests include KRAS, EGFR, HER2, tumor genome profiling tests (with lots of different genes) and tumor karyotyping.
2.The Genetics of You
A subset of all cancer patients (about 5-10% or 1 in 15) were born with increased chances of developing cancer. These patients usually have family members who have or have had cancer, often get cancer at younger ages, and are more likely to get more than one cancer diagnosis. Often these types of cancers are called hereditary cancers.
When you have a test for a hereditary cancer, these tests are usually designed to help you understand
1) Why you got cancer
2) Whether you have increased chances of getting another cancer
3) Whether your family members might have increased chances of getting cancer
More and more, these types of tests are also helping to make decisions about how you can screen for cancer, if there are ways to reduce risk of cancer, and in some rare cases, how you can treat your cancer to match your genetic background.
Common “genetics of you” tests are BRCA1 & 2 (for breast and ovarian cancer), MLH1 & MSH6 (for colon and uterine cancer) and APC (for colon cancer associated with polyposis).