According to the results of a meta-analysis of 12 studies, which included more than 10 thousand patients with breast cancer, it was found that the frequency of complete pathomorphological response to treatment with Trastuzumab in neoadjuvant mode was the lowest in the luminal A subtype (7.5%), and in the most prognostically unfavorable subtypes was 50.3% in HER-2 positive patients and 33.6% in the triple-negative subtype [67]. The gene discussed is ERBB2; the disease is breast carcinoma.