ERBB2 and neoplasm: A tumor is considered HER2-positive if it exhibits full and intense circumferential HER2 IHC staining in more than 10% of cells (score 3+) and/or if the gene is amplified with an average HER2 gene copy number of more than 4.0 signals per cell and a HER2/CEP17 ratio of more than 2 [12].