A model is described by which in vivo tumor-MOAB interactions may be investigated. The method is rapid and may aid in the selection of appropriate MOABS from a panel of MOABS for individualized patient treatment. Groups of athymic nude mice were injected intravenously with small cell lung cancer line SHP-77 cells which are trapped primarily in the lungs. Twenty-four hours post tumor cell inoculation, 186Rhenium tagged HNK1 MOAB (CD57) was injected intravenously. Controls which received no tumor cells were injected with unbound 186Re or radioactive MOAB. Biodistribution studies at 24 hours following MOAB injection showed significantly more radioactivity in lungs of mice inoculated with both SHP-77 cells and 186Re MOAB than did lungs of controls.