Immunohistochemistry (IHC) is the most common screening test used to detect HER2 protein expression in BC and may easily identify negative (score 0/1+) and positive (score 3+) cases whereas IHC 2+ equivocal results, occurring in up to a quarter of BC, need a reflex in situ hybridization (ISH) test to identify HER2 positive cases [10]. Here, ERBB2 is linked to breast cancer.