ERBB2 and triple-negative breast carcinoma: Four distinct breast cancer subtypes have been classified based on the expression of the proliferation marker (Ki67) and the hormonal status including Luminal A, Luminal B (HER2 negative), Luminal B (HER2 positive), HER2 (non-luminal) and triple-negative breast cancer (TNBC) [2] (Table 1).