MiR-193b level was higher in tissues of patients with tumors > 2 cm in HER2 0 BC; miR-324—in luminal B HER2-non-amplified; miR-423—in luminal A. MiR-200b expression was reduced in tumors > 2 cm compared to smaller tumors in BC with Ki-67 < 14%. The gene discussed is ERBB2; the disease is breast cancer.