Notably, recent reports demonstrate that resistance to combined inhibition of PI3K and HER2 in HER2+ breast cancer is associated with upregulation of collagen, integrin β1, and Src activity (48), suggesting that inhibiting both PI3K and Src may overcome resistance to the HER2-targeted therapy better than inhibiting just PI3K or Src alone. This evidence concerns the gene ERBB2 and breast carcinoma.