ERBB2 and breast cancer: Gallen International Breast Cancer Conference 2011 allocated four molecular subtypes to breast cancers: Luminal A (ER+/PR+/HER2-/lowKi-67); Luminal B (ER+/PR+/HER2-/+/high Ki-67); HER2-overexpression (ER-/PR-/HER2+) and triple negative breast cancers (TNBCs) (ER-/PR-/HER2-) [2].