This difference was significant in the subgroup of women with ER positive BC who received HER2 targeted therapy, here the IHC 3+ tumours showed a pCR rate of 58% compared to 15% in the IHC 2+ FISH amplified Groups (1, 2 and 3; 19/123) (p < 0.0001), but not in the ER negative subgroup (pCR rate of 53% for IHC 3+ versus 38% IHC 2+ amplified, (p = 0.68)) (Table 2). The gene discussed is ERBB2; the disease is breast cancer.