Representative flow cytometric analysis of ALL (G2 and KK) and AML (AML-1, -2, -3, and -5) cell lines after exposure to lovastatin. The percentage of cells in the pre-G1 (apoptotic) fraction is shown in the upper left quadrant of the individual histograms. Cells were exposed to solvent control (left column), 20 μmol/L lovastatin treatment for 1 day (center column), or 20 μmol/L lovastatin treatment for 2 days (right column).