Fig. 2

Chemotherapy regimens and trends of serum calcium (uncorrected) and serum human epidermal growth factor receptor 2 protein in case 2. Severe hypocalcemia recurred on the 56th day of letrozole therapy, on the 42nd day of trastuzumab emtansine therapy, on the 35th day of lapatinib and capecitabine therapy, and on the 21st day of resumed lapatinib and capecitabine therapy. The serum human epidermal growth factor receptor 2 protein levels decreased after the initiation of the trastuzumab emtansine or lapatinib and capecitabine therapies, showing a tendency to correlate with the trends in serum calcium levels