Thirty to seventy-five percent of patients with HER2 positive breast cancer achieved pCR following neoadjuvant chemotherapy combined with HER2-targeted therapy - a significantly higher percent compared to neoadjuvant chemotherapy of breast cancer overall (all breast cancer subtypes combined) which attain a pCR of 20% at its most successful (4, 5, 32, 33, 56, 57). This evidence concerns the gene ERBB2 and breast carcinoma.