Provided is an antibody or fragment thereof derived from monoclonal antibody SC104 comprising a VH domain wherein the VH domain comprises three CDRs wherein the sequence of CDR1 is amino acids 44 to 49 or 44 to 54 of SEQ ID NO: 23 or a sequence at least 70% identical thereto and wherein the antibody or fragment thereof binds Colo205 cells. The antibodies can be used to treat various tumours.