A. MDA-MB-231 cells and four p57-deficient derivatives 9, 11, A and E were treated with BMS-387032 for 48 hrs. Cell extracts were subjected to western blots using p57, E2F1 and actin antibodies as indicated. The fourth lane appears under loaded, and this is due to the large amount of cell death in this treatment. B. The growth rates of MDA-MB-231 cells and four p57-deficient derivatives were determined. Fourty thousand cells per were plated in 24-well plates in ten wells on day 0. Two wells were harvested by trypsin, collected and counted each day. Plotted numbers represent the average.