A 54-year-old woman with no significant family or social history potentially related to BC was initially diagnosed with clinical stage IV (cT2cN1(f)M1) IDC of the right breast that was ER+/PR+ (90%/75%) and HER2+ (>30%) as well as high-grade ductal carcinoma in situ of the right breast (Figure 1). Here, ERBB2 is linked to breast cancer.