ERBB2 and neoplasm: To investigate the effects of increased valency of respective target modules and the distance between UniCAR and tumor-cell binding domains on UniCAR activity, we developed different homodimeric TM designs with one, two or three E5B9 peptides per TM monomer, with the ErbB2-specific scFv antibody fragment and UniCAR epitopes either directly linked or separated by an IgG4 Fc domain.