A state-of-the art collection of readily reproducible laboratory methods for assessing chemosensitivity in vitro and in vivo, and for assessing the parameters that modulate chemosensitivity in individual tumors. Chemosensitivity, Volume 1: In Vitro Assays provides a panel of 16 in vitro measures of chemosensitivity in adherent and non-adherent cells for single agents and combinations of agents. In addition to immunohistochemical and imaging approaches, these assays include clonogenic, colorimetric, fluorometric, and physiological assays. Highlights include image analysis to assess drug sensitivity, high throughput approaches using green fluorescent protein, DIMSCAN (a microcomputer fluorescence-based assay), and the ChemoFx assay used in biotechnology. A companion volume, Volume 2: In Vivo Models, Imaging, and Molecular Regulators, provides protocols for classifying tumors into response categories and customizing chemotherapy regimens to individual patients.