Classification of patients according to CRAC values in relation to leukemia cell persistence in bone marrow on day 15 of induction treatment. Patients (n = 63) were grouped according to CRAC, indicating proficient (CRAC positive, n = 27) or deficient (CRAC negative, n = 36) cytochrome c–related caspase activation. The percentage of leukemia cells in bone marrow after 15 days of remission induction treatment is given on the y-axis. Bars indicate mean values; P value of independent samples t test.