The 21-gene assay is a prospectively validated predictive and prognostic tool. It is based on reverse transcriptase polymerase chain reaction and integrates the expression of 16 genes known to be related to breast cancer and five reference genes. A recurrence score is generated that correlates with the likelihood of distant recurrence at 10 years. It is used clinically to determine the prognosis in women with hormone receptor (HR)-positive, HER2-negative disease who are treated with endocrine therapy alone by predicting locoregional and distant recurrence. This assay has also been validated to predict the benefit of adding adjuvant chemotherapy to adjuvant endocrine therapy for women with HR-positive, HER2-negative, breast cancer that is either node-negative or with up to three positive lymph nodes.
Patients at high risk for recurrence can also be identified by other multigene assays, such as the 70-gene prognostic signature, the 50-gene assay (PAM-50), and the 12-gene molecular score. However, these have not been prospectively validated to predict the benefit of adjuvant chemotherapy. Only one assay should be ordered for a specific patient and tumor, as the results of the different assays may be discordant and those assays have not been prospectively compared in head-to-head studies.
Learn more about molecular profiling assays in breast cancer.
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Cite this: Elwyn C. Cabebe, Stefania Morganti. Fast Five Quiz: The Recurrence Risks for Breast Cancer - Medscape - Feb 06, 2023.