Recently, an automated microculture kinetic (MiCK) assay for measuring drug induced apoptosis in tumor cells has been developed1-4. Apoptosis is a distinct mode of cell death which occurs under physiological conditions and yet can be induced in malignant cells by chemical and physical factors including antitumor drugs5-7. During the last decade, it has been recognized that chemotherapeutic agents exert their antitumor activity by triggering apoptosis in susceptible tumor cells8-17. This implies that the MiCK assay for apoptosis provides a mechanism-based approach to studying effects of cytotoxic agents on tumor cells. Unlike "resistance" assays that measure a fraction of cells surviving drug exposure, the MiCK assay measures a fraction of tumor cells killed by a chemotherapeutic agent via mechanism of apoptosis. Therefore the MiCK assay determines drug sensitivity, rather than resistance. Recently the MiCK assay has been shown to predict complete remission rate and survival in acute myeloid leukemia patients better than clinical criteria did18-20. In a limited study, the MiCK assay has been used to direct chemotherapy of the leukemia patients 21.