Clinical utility of gene-expression signatures in early stage breast cancer

Breast cancer is not a single, homogenous disease, but a heterogeneous group of different disease subtypes, each with its own biological and clinical characteristicsMethods to enhance the identification of individuals with high-risk disease, who would benefit from more-intensive treatment are an area of expanding research interestThe development of multigene assays has led to improvements in predicting the risk of recurrence in patients with early stage oestrogen receptor (ER)-positive, HER2-negative breast cancer, compared with use of standard prognostic criteriaSeveral multigene assays, including Oncotype DX, Prosigna, and MammaPrint have emerged as well-studied technologies and have already been incorporated into clinical practice, to some extentIn 2016, the ASCO Breast Cancer Guidelines Advisory Group and Clinical Practice Guidelines Committee published updated guidelines for the use of biomarkers, including gene-expression assays, to help guide the use of adjuvant systemic therapySeveral large, randomized trials are currently ongoing and aim to prospectively evaluate and further validate the performance of these assays, in order to provide the highest level of evidence of clinical utility