The P-gp positivity in oligonucleotide-treated AML blast cells (Case No. 8; 2.5 μmol/L) after incubation with oligonucleotide-free medium. After random (▧), MDR1-S (▧), and MDR1-AS (▪) treatment, these cells were incubated with oligonucleotide-free medium for 1 to 7 days, and P-gp was measured using flow cytometry. Results represent the mean of two experiments.