Among 205 patients in whom HER2 status was evaluated both in the primary tumor and in a metastatic lesion, we observed a tumor shift of HER2 status in 72 (35%) patients, including 34 (17%) tumors shifting from HER2-0 to HER2-low status and 34 (17%) tumors shifting from HER2-low to HER2-0 status (Supplementary Table 2, Supplementary Fig. 1). The gene discussed is ERBB2; the disease is neoplasm.