Among 668 tamoxifen-treated patients in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-14 clinical trial [12], the Recurrence Score was strongly predictive of risk for distant recurrence, both alone and in multivariate analyses that also included patient age, tumor size, tumor grade, and ER and HER2 status. The gene discussed is ESR1; the disease is neoplasm.