ERBB2 and neoplasm: In this patient, HER2 status of the primary tumor converted from positivity to negativity after NAC, which is in accordance with the results of one preclinical study [13] showing that paclitaxel downregulated HER2 expression in MDA-MB 453 cells and one retrospective study by Niikura et al. [14], which showed that 21.4% of HER-2 positive primary tumor had lost HER-2 expression in a neoadjuvant setting, and strongly supported the necessity to retest HER-2 status of residual tumor after neoadjuvant therapy in order to accurately determine appropriate utilization of anti-HER-2 therapy.