Homodimeric EGFRxEGFR and HER2xHER2 T-BsAbs were heterodimerized with a CD33-specific control T-BsAb, generating EGFRxCD33 and HER2xCD33 T-BsAbs bearing one tumor-targeting Fab and one non-tumor-targeting CD33 control Fab. This evidence concerns the gene CD33 and neoplasm.