More recently developed, the EndoPredict assay (EP) (Sividon Diagnostics GmbH, Cologne, Germany), is a test based on gene expression data in combination with two clinicopathological risk parameters (tumor and nodal status) to assess the risk of distant metastasis in patients with ER+/HER2- primary breast cancer if treated with adjuvant endocrine therapy alone [8]. The gene discussed is ESR1; the disease is breast cancer.