ERBB2 and cancer: We here exemplarily explored the retargeting of the CD19-specific CAR T cells towards the ErbB2+ cancer cells, while mainly sparing the ErbB2+ healthy fibroblasts, through a fusion protein that consists of the ErbB2 targeting single chain variable fragment (scFv) antibody 4D5, fused to the extracellular domain of CD19 that is recognized by the CAR delivering the CD28 and CD3ζ stimulation to the engineered T cell upon binding [2].