High throughput drug screening assay methods and related apparatus are described. Drosophila with screenably distinct characteristics are raised in multi-well microtiter plates on standard growth medium. Screenably distinct characteristics which mimic human cancer or cancer-related condition are established by modifying expression of an oncogene or tumor suppressor in the Drosophila. Compounds that putatively modify the screenably distinct characteristic are then tested by feeding the compounds to the Drosophila embryos, and determining whether the compound modifies the screenably distinct characteristic induced by modifying gene expression. The assay methods and related articles of composition can also be used to simultaneously assay toxicity of candidate compounds.