RRM2B and metastatic neoplasm: RRM2B status was significantly associated with median age at randomization (P = 0.03), bone metastases (P = 0.03), HER2 status (P = 0.01), prior chemotherapy for locally advanced or metastatic disease (P = 0.02) (Additional file 2: Table S2), and PAM50 subtype (P = 0.0004) (Table 2).