The identification of peptide epitopes with techniques such as phage display peptide libraries has opened the opportunity to develop specific targeting molecules for a variety of antibody-based biomedical applications.We are exploiting these peptides for the study of B-cell leukemias such as Multiple Myeloma (MM) in which oncogenic transformation occurs post antigenic stimulation.These tumor cells produce and secrete clonotypic antibody that can be targeted for the purposes of biomarker identification or therapy.For example, we demonstrate that (peptide or small molecule) antigen-drug conjugates not only allow for targeted, tumor cell killing but these conjugates do not induce drug resistance.