Sensitivity of HL cell lines to imatinib. The 4 HL cell lines KMH2 (▪), HDLM2 (▴), L1236 (▾), and L428 (♦) were incubated for 70 hours with the indicated imatinib concentrations. After incubation in propidium iodide, numbers of living cells were determined in a FACScan. Experiments were repeated 3 times, and a representative experiment with 3 replicates and standard derivation is shown in a semi-logarithmic plot. Numbers of living cells are shown as fractions (in percentages) of the untreated control.