ERBB2 and breast cancer: Microarray profiling classifies breast cancer into four molecular subtypes (luminal (A and B), HER2-positive and triple-negative breast cancer (TNBC)) with distinct gene expression patterns and clinical outcomes [3,4,5]; HER2-positive and TNBC subtypes are comparatively aggressive [6,7] and lack hormone receptors and hence are known as receptor negative breast cancers [8].