A recent study revealed that in patients with HER2-negative primary breast cancer, residual disease was observed following neoadjuvant chemotherapy, the overall rate of HER2 status change was 32.4%, including 1.1% shifting from HER2-negative to HER2-positive, transition rates included 15.4% shifting from HER2-low to HER2-zero and 15.9% moving from HER2-zero to HER2-low (49). The gene discussed is ERBB2; the disease is breast cancer.