Heterodimeric bispecific immunoglobulin molecule comprising (i) a first Fab or scFv fragment which specifically binds to EGFR, wherein the first Fab or scFv fragment is derived from cetuximab and comprises VL and VH sequences selected form the group consisting of SEQ ID NO: 9, SEQ ID NO:10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, and (ii) a second Fab or scFv fragment which specifically binds to c-MET, wherein the second Fab or scFv fragment comprises VL sequences selected from the group consisting of SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19, SEQ ID NO: 21, SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27, SEQ ID NO: 29, SEQ ID NO: 31, SEQ ID NO: 33, SEQ ID NO: 47, SEQ ID NO: 49, SEQ ID NO: 51, and wherein the VH sequences of said second Fab fragment are selected from the group consisting of SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, SEQ ID NO: 30, SEQ ID NO: 32, SEQ ID NO:34, SEQ ID NO: 48, SEQ ID NO: 50, or SEQ ID NO: 52, and (iii) an antibody hinge region, an antibody CH2 domain and an antibody CH3 domain comprising a hybrid protein-protein interaction interface domain wherein each of said interaction interface domain is formed by amino acid segments of the CH3 domain of a first member and amino acid segments of the CH3 domain of said second member, wherein said protein-protein interface domain of the first chain is interacting with the protein-protein-interface of the second chain by homodimerization of the corresponding amino acid segments of the same member of the immunoglobulin superfamily within said interaction domains, wherein the first or second engineered immunoglobulin chain has the polypeptide sequence ("AG-SEED"): GQPFRPEVHLLPPSREEMTKNQVSLTCLARGFYPX 1 DIAVEWESNGQPENNYKTTP SRQEPSQGTTTFAVTSKLTX 2 DKSRWQQGNVFSCSVMHEALHNHYTQKX 3 ISL (SEQ ID NO:1), wherein X 1, X 2 and X 3 may be any amino acid, and wherein the first Fab fragment binds EGFR with an K D of at least 5x10 -8 M, and wherein the second Fab fragment binds c-MET with an K D of at least 5x10 -8 M. (i) a first Fab or scFv fragment which specifically binds to EGFR, wherein the first Fab or scFv fragment is derived from cetuximab and comprises VL and VH sequences selected form the group consisting of SEQ ID NO: 9, SEQ ID NO:10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, and (ii) a second Fab or scFv fragment which specifically binds to c-MET, wherein the second Fab or scFv fragment comprises VL sequences selected from the group consisting of SEQ ID NO: 15, SEQ ID NO: 17, SEQ ID NO: 19, SEQ ID NO: 21, SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27, SEQ ID NO: 29, SEQ ID NO: 31, SEQ ID NO: 33, SEQ ID NO: 47, SEQ ID NO: 49, SEQ ID NO: 51, and wherein the VH sequences of said second Fab fragment are selected from the group consisting of SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, SEQ ID NO: 30, SEQ ID NO: 32, SEQ ID NO:34, SEQ ID NO: 48, SEQ ID NO: 50, or SEQ ID NO: 52, and (iii) an antibody hinge region, an antibody CH2 domain and an antibody CH3 domain comprising a hybrid protein-protein interaction interface domain wherein each of said interaction interface domain is formed by amino acid segments of the CH3 domain of a first member and amino acid segments of the CH3 domain of said second member, wherein said protein-protein interface domain of the first chain is interacting with the protein-protein-interface of the second chain by homodimerization of the corresponding amino acid segments of the same member of the immunoglobulin superfamily within said interaction domains,