Correlation between imatinib resistance level and frequency of mutations isolated from patients. The fold-increase in IC₅₀ value for inhibition of cell proliferation by imatinib compared with cells expressing native Bcr-Abl is plotted on the abscissa versus the clinical frequency in patients (%). As described in Hughes et al,³  the results are compiled from 20 studies. To allow for better comparison, only mutants whose IC₅₀ was determined in the same laboratory were included in the analysis. Unlabeled points represent M244V, G250E, Q252H, F311L, F317L, E355G, F359V, V379I, L387M, H396P, and H396R.