ERBB2 and triple-negative breast carcinoma: Pre-specified exploratory subgroups analyses by histopathologic, patient, and treatment related characteristics showed a trend towards benefit in patients with advanced stage (defined as stage IIB or greater) and HER2 under-expression (HER2 UE, defined as HER2 expression IHC 1–2 + and/or positive FISH 1.2–2.0), and triple-negative breast cancer (TNBC, Fig. 4).