However, it seems that we cannot extrapolate these findings from AML cell lines to the clinical setting, because P-gp activity in HL60/DNR, K562/HHT40, K562/HHT90 and K562/DOX cells showed D values of 0.98 ± 0.004, 0.41 ± 0.01, 0.83 ± 0.05 and 0.99 ± 0.01 respectively, which are far higher than those observed in the AML patient cells. This evidence concerns the gene PGP and acute myeloid leukemia.