Breast Cancer Multiparameter Gene Expression Tests 3
As a category, multiparameter gene expression tests for breast cancer are relatively new, although their use is increasing. They require a minimum quantity of tumor tissue and specific sample processing. Many of these assays are effective in tissue that has been preserved in some way and stored for a period of time (archival tissue), which allows for the evaluation of patients well after surgery. Each has been developed to be used in specific populations of patients. They have the potential of helping to identify those with the highest and lowest risk of breast cancer recurrence.
Most frequently ordered tests include:
- MammaPrint® test
- Evaluates the expression profile of 70 genes
- Cleared for marketing by the U.S. Food and Drug Administration (FDA)
- For newly diagnosed patients with Stage I or II breast cancer that is equal to or less than 5 centimeters (2 inches) that fall into one of the two criteria:
- Women with estrogen receptor-positive or progesterone receptor-positive, HER2-negative, node-negative breast cancer who are at a high clinical risk of recurrence based on standard prognostic factors, such as age, tumor size and tumor grade
- Women with estrogen receptor-positive or progesterone receptor-positive, HER2-negative breast cancer with 1-3 positive lymph nodes who are at a high clinical risk of recurrence
- This test should not be used in women who have a low clinical risk for recurrence.
- Requires availability of preserved, fresh or frozen breast tumor sample
- Categorizes women into a high versus low risk for recurrence within 10 years. It can help inform decisions on whether a woman would benefit from chemotherapy after surgery. Women meeting either of the above criteria who have a low MammaPrint score may be treated with hormone therapy alone because they are unlikely to benefit from chemotherapy.
- Included in American Society of Clinical Oncology (ASCO) guidelines
- Available from locations in the U.S. and in the Netherlands
- Oncotype DX® Breast
- Evaluates the expression profile of 21 genes
- For newly diagnosed patients who have Stage I or II breast cancer that is estrogen receptor positive and has not spread to the lymph nodes
- Requires preserved tumor tissue
- Used to predict the risk of recurrence in patients treated with tamoxifen and assesses the benefit of other chemotherapy regimens (i.e., CMF, methotrexate/5-fluorouraci/leucovorin); some women with low or intermediate risk scores may be able to forego chemotherapy.
- Included in the American Society of Clinical Oncology (ASCO) guidelines, in guidelines from the National Comprehensive Cancer Network (NCCN), and is addressed by the National Breast Cancer Coalition (NBCC)
- Commercially available from one laboratory
Many other multi-gene or multi-gene expression assay systems have been developed. ASCO guidelines also recommend:
- EndoPredict–a 12-gene risk score that may be used to guide decisions for chemotherapy in patients with ER/PR-positive, HER2-negative (node-negative) breast cancers
- PAM50 ROR– this test evaluates 50 genes and uses the information to predict if a cancer will metastasize. The score may be used in conjunction with other variables to guide decisions on adjuvant therapy if a patient has ER/PR-positive, HER2-negative (node-negative) breast cancer
- Breast Cancer Index–may be used to guide decisions on adjuvant therapy if a patient has ER/PR-positive, HER2-negative, node-negative breast cancer
Clinical trials are continuing to address the use of gene expression tests:
- The TAILORx (Trial Assigning Individualized Options for Treatment) trial is comparing adjuvant hormonal therapy with adjuvant combination of chemo and hormonal therapy in women with an Oncotype DX intermediate risk Recurrence Score.
- The RxPONDER (Rx for Positive Node, Endocrine Responsive Breast Cancer) is designed to confirm that breast cancer that is ER-positive and has spread to a lymph node (node-positive) can be successfully treated with hormonal therapy with or without chemotherapy based on the Oncotype DX risk scores.
- The MINDACT (Microarray In Node-Negative Disease may Avoid Chemotherapy) trial is comparing the MammaPrint test with certain traditional (clinical and pathologic) criteria in assigning patients to chemotherapy treatment.
These trials, and future trials, will further delineate the clinical usefulness of the tests and will evaluate their ability to help guide breast cancer therapy. While it will be a number of years before results from trials are conclusive, healthcare providers may decide to use these molecular tests in monitoring and treating patients with breast cancer on an individual basis. If you would like to know more, talk to your healthcare provider about whether one of these tests might be right for you. You may also wish to check whether your health insurance will cover the cost of testing.
For additional details on these and other similar tests, visit the following web sites:
- National Comprehensive Cancer Network
- American Society of Clinical Oncology
- National Breast Cancer Coalition
© 2017 American Association for Clinical Chemistry, republished from Lab Tests Online.*
Descriptions of clinical laboratory tests were originally prepared for use on Lab Tests Online, an award-winning patient education website on clinical laboratory testing. Lab Tests Online is produced by the American Association for Clinical Chemistry (AACC), a global scientific and medical professional organization dedicated to clinical laboratory science and its application to healthcare. The Lab Tests Online website is developed in collaboration with other laboratory professional societies and is funded in part through corporate sponsorships.