Genetic testing is a rapidly evolving field with a wide range of testing options from a variety of labs. Many factors are taken into consideration prior to ordering testing. This overview provides general information on the different types of current genetic testing, all of which are available via Harold C. Simmons Comprehensive Cancer Center.
Genetic testing can identify people at higher risk for developing cancer. Genetic testing is currently available for more than 20 hereditary cancer syndromes and more than 50 hereditary cancer genes, and the list is growing.
At the same time, genetic testing technology is continually evolving. As a result, it’s important to review previous genetic test results to determine if changes to testing technology or additional genes are now available.
As an NCI-designated comprehensive cancer center, we offer consultation to discuss many types of genetic tests, including:
- Direct-to-Consumer Testing
- Panel Testing
- Single-Site Testing
- Somatic (Tumor) Testing
- Specific-Gene Testing
- Treatment-Guided Genetics
When to Offer Genetic Testing
According to the ASCO Policy Statement Update: Genetic Testing for Cancer Susceptibility (2003), genetic testing should be offered when:
- The patient has a reasonable likelihood of carrying the altered cancer susceptibility gene based on risk model estimations, established guidelines, or insurance criteria
- A genetic test is available that can be adequately interpreted
- Results will influence medical management
- The patient wants the information and meets the above criteria
There are certain patients that may not yield reliable results from genetic testing. Two subsets of such patients are those who received bone marrow transplants and have hematologic malignancies.
Bone Marrow Transplant Recipients
- Bone marrow transplant recipients are known to express donor DNA in both blood and saliva. Therefore, genetic test results from blood or saliva of bone marrow transplant recipients are unreliable.
- If genetic testing is needed for a patient who has undergone a BMT, cultured fibroblasts are felt to be a reliable source of DNA. Blood and saliva samples should not be used for testing these patients.
Patients with Hematologic Malignancies
- Patients with current hematologic malignancies (e.g., leukemia or myelodysplastic syndrome) have an increased number of malignant cells in their blood. Genetic testing laboratories will not typically accept blood samples from these patients due to the high quantity of cancer cells that could affect the accuracy of germline genetic testing.
- Cultured fibroblasts or fresh/frozen normal tissue may be an option. Specific limitations and requirements should be discussed with a genetic counselor and testing facility prior to testing.