Payloads such asMMAE are cell-permeable once released from their drug carriers andcan promote bystander killing of neighboring cells.57 The radiation-activated strategy may therefore be relevantfor targeting tumor-associated stromal cells via targets such as fibroblastactivation protein (FAP),58 targeting tumor-associatedmacrophages that phagocytose albumin and other drug delivery vehicles,59,60 and potentially in concert with delivering therapeutic radionuclidesto targets such as FAP and somatostatin receptor subtype 2 (as withclinically used lutetium Lu-177 dotatate). The gene discussed is FAP; the disease is neoplasm.