Many patients are interested in learning about our testing and so we have provided some more detailed information about the tests we use.
Your doctor will also discuss the meaning and outcomes of the tests.
Genetics and Cancer
Your body is made up of tiny building blocks called cells. Every cell in your body contains a copy of your genes. Genes are the “instruction manuals” that provide all the information your body needs to grow and develop. Cancer is caused when a small group of cells in the body develops changes in the genetic code, also called mutations. These mutations cause the cells to grow too fast and invade other parts of the body. Mutations can occur as a normal part of aging, by random chance, or as the result of certain environmental exposures, or by random chance.
In most cases, all the mutations in a cancer developed only a small group of cells in the body, so all the mutations are found only in the tumor. In other cases, a person is born with one a mutation that was inherited from the mother or father and is in every cell of his or her body. People who are born with one a genetic mutation are more likely to get cancer than other people, as they go through life and develop additional mutations.
This test has two parts:
- Testing of a tumor sample from a surgery or biopsy
- Testing of non-tumor (normal) cells from a blood or saliva sample
Testing of Tumor Cells
When tissue is removed during a biopsy or a surgery, the doctor sends it to a pathology laboratory for further testing. Your doctor is also going to send some of this tissue for the UCSF 500, a test to look for genetic mutations that occurred during the growth of your tumor. These genetic mutations are only in the tumor cells and are not inherited from a parent or passed down to children. By studying the genetic changes that have are making your tumor grow, your doctor may find new treatments for your type of cancer.that work directly on those specific mutations.
Testing of Non-Tumor Cells
Your doctor will also send a sample of your normal blood or saliva as a part of the UCSF 500. These normal cells will also be tested for mutations. Genetic changes found in normal blood or saliva cells are called “germline mutations,”, which means that they are were inherited from your parents and are in every cell of your body. Some germline mutations cause an increased chance of developing cancer. (These mutations are also likely to be found in your tumor, since they are in all your cells.)
Finding a germline mutation that has been linked to inherited cancer risk is very important information to help you and your family members. If a mutation is found that increases your chances of another cancer in the future, there are things you can do to prevent a future cancer or catch it at an early stage. Also, if you have an inherited germline mutation, it is possible that some of your relatives also have this the germline mutation. Your relatives can have genetic testing to find out if they have the same inherited mutation. If they also have this mutation, they can also take steps to prevent cancer or catch it early. Some of your relatives could also find out they do not have the mutation, and they do not have an increased risk of cancer.
What will the Results Mean?
Your doctor will discuss the results of the UCSF 500 with you. This test may help your care team understand the best treatment for you based on your tumor’s profile. This test may also give information about the cause of your cancer and your chances of developing cancer in the future, if a germline mutation is found. Because we share our germline genes with our family members, this information may also have implications for your relatives. If a germline mutation is found, your doctor will refer you to a genetic counselor to discuss this in greater detail.
Although this test can find inherited germline mutations, the main purpose of this test is to help your doctors determine the best treatment for your cancer. Therefore, if you would like to get more information about the history of cancer in your family and how it affects you and your relatives, you should speak with a genetic counselor at the phone number below.
CLIA Number: 05D2034158
California State License Number: CLF00341585
Where can I get More Information?
- UCSF Cancer Genetics and Prevention Program (Genetic counselors): 415.885.7779
Exome Sequencing for Undiagnosed Diseases
The test that is performed is called the Clinical Exome Sequencing test. This information will be discussed with you by a medical geneticist and/or genetic counselor.
What is the Benefit of the Clinical Exome Sequencing test?
The Clinical Exome Sequencing test is used to identify the genetic cause of a disease or disability in an individual. Genes carry inheritable information, and it is estimated that we have about 20,000 genes in the cells in our body. The combination of all genes in an individual is called the genome. Some important and functional sections of the genome that make protein are called exons. The word ‘exome’ refers to all exons in the genome.
This test analyzes the exons of about 93-97% of all medically relevant genes at the same time and compares it to those of healthy people to identify DNA changes that are related to the individual’s medial condition. We do this to try to find the DNA change that has led to your medical condition. The benefit of receiving the information from this test, in conjunction with available published medical information at the time of testing, is to decide whether these DNA changes are likely to be causing your medical condition.
What are the Limitations and Risks?
It is important to understand that there may be DNA changes (also called variants) that will not be related to your disease (incidental findings). The symptoms of these other conditions may not be evident at this time, and they may or may not develop in the future. During the course of reviewing your results, we may encounter certain incidental findings which we deem to be medically actionable (where you and/or your physician may want to take action for your future medical benefit).
There are some types of DNA changes that cannot be detected by this test. This test is targeted to analyze the exons; however, there are parts of the exome that are undetectable. In addition, we know that some disease-causing variants do not occur in exons, and this test will not detect those variants either. Your physician may decide that you need other DNA testing in addition to this test. The testing process relies on highly skilled technicians and reliable technology. The methods are reliable, but as with any laboratory test, there is the small chance that an error may occur.
Will my Results impact my Family Members?
In some instances we might need to test other family members to make the result clear. There is a risk that you may learn genetic information about you or your family members that is not related to the medical concern for which this test is ordered. Learning about this information might cause anxiety and psychological stress. This information might reveal:
- genetic risks for diseases that may develop later in life
- diseases unrelated to the primary reason for ordering the Clinical Exome Sequencing test
- disorders that do not have current treatments
- non-paternity and non-maternity (the father or mother is not the biological parent) or other unexpected familial relationships
How will I Learn about the Results?
Clinically significant variants associated with your primary clinical concern(s) will be reported to your physician.
If your child or family member is having the Clinical Exome Sequencing test performed, you may be tested in order to assist with the analysis of your child’s or family member’s sample and will not receive a separate report specific to your genetic results. A report will only be generated for your child or family member. If you are found to share the same genetic finding(s) with your child or family member, that information will be included in his/her report.