ERBB2 and neoplasm: Using a panel of xenografts with well characterized HER2 and PIK3CA status to examine the treatment effect of cisplatin and 5-fluorouracil, tumor xenografts negative for HER2 and carrying wild-type PIK3CA were more sensitive to such treatment when comparing to HER2-positive xenografts irrespective of the mutation status of PIK3CA [26].