According to international clinical practice guidelines, neoadjuvant systemic therapy is indicated for HER2-positive early breast cancer when tumors are ≥  2 cm, node-positive, or when downstaging is needed for breast conservation, but is not routinely recommended for small (≤ 1 cm), node-negative tumors, for which primary surgery is generally preferred [4, 9]. The gene discussed is ERBB2; the disease is breast cancer.