Abstract: With the recently increasing number of the women newly diagnosed with early breast cancer(EBC),the 21-gene recurrence score assay has been clinically validated and recommended for the treatment decision making in patients with ER(+), node-negative(N0) EBC. A growing body of evidence from several large phase Ⅲ clinical trials reports similar findings in patients with ER(+), N(+) EBC. This assay could help guide treatment decisions for the patients who are most likely to receive benefit from chemotherapy.