MKI67 and breast cancer: EMITEBC-1 (Establishment of Molecular Profiling for Individual Treatment decision in Early Breast Cancer; NCT03904173) is a national, prospective, observational multicentre single-arm trial designed to assess the value of Prosigna as a routine diagnostic tool, examining its impact on adjuvant treatment decisions (versus standard histopathology including Ki67), clinical outcomes, long-term side-effects and cost-effectiveness.