Fold increase in biochemical and cellular IC₅₀ values of reported kinase domain mutants. A graphic representation of mutant sensitivities to imatinib. Mean fold differences are shown. Mutants whose cellular IC₅₀ values are near or below reported trough levels of imatinib (1.46 μM) in patients treated with 400 mg⁴  are marked with an asterisk. For space considerations, single-letter amino acid codes are used here in place of 3-letter codes.