One protein known to interact with the α-subunit and be overexpressed on the cells of many metastatic cancers is dysadherin (DYS) a gamma subunit of the NKA (also known as a FXYD family protein).26 Hence, we constructed a new type of antibody drug conjugate (ADC) that targets extracellular protein-protein interactions and termed these, extracellular drug conjugates or EDCs. The gene discussed is FXYD5; the disease is metastatic malignant neoplasm.