ERBB2 and gastric cancer: We next examined gastric cancer-derived ERBB2 amplified OE19 cells that are sensitive to lapatinib and found that a combination of lapatinib plus prednisone is more effective than lapatinib alone in a xenograft model (Fig. 6d) and also detect a suppression of bypass RTK signaling by prednisolone (Supplementary Fig. 17).