Taking hormone receptor statuses into consideration, breast cancer as the subsequent primary cancer (SBC) was significantly associated with short BCSS and OS in HER2-/HR+ patients (both P < 0.001, Figure 5A, 5B) and HER2+/HR+ patients (P = 0.001and P < 0.001) (Figure 5E, 5F). This evidence concerns the gene ERBB2 and cancer.