Fig. 4

HER2 alterations on CTCs of metastatic breast cancer patients (n = 14) after trastuzumab administration. a Number of total CTCs per patient before and after trastuzumab-based chemotherapy. b Number of CK-positive/HER2-positive-expressing CTCs per patient before and after trastuzumab-based chemotherapy. c Number of p95HER2-expressing CTCs per patient before and after trastuzumab-based chemotherapy. d Number of CK-positive/HER2-negative-expressing CTCs per patient before and after trastuzumab-based chemotherapy.CK cytokeratin, CTCs circulating tumor cells, HER2 human epidermal growth factor receptor 2, p95HER2 the truncated form of HER2