Inthe Russian female population in 2017, breast cancer accounted for 21.1% ofmalignant neoplasms; the number of patients with stage I–II of thedisease amounted to 69.9% [1].Overexpression of the epidermal growth factor receptor ErbB2 was detected in asignificant percentage of the tumors. The gene discussed is ERBB2; the disease is neoplasm.