The comprehensive evaluation on four indices of drug resistance in acute myeloid leukemia

To study sensitivity of drug resistance indexes and resistance manner in acute myeloid leukemia (AML), MTT drug sensitivity, growth types of CFU-L in vitro, Bcl-2 antigen and Bcl-2/Bax ratio and intracellular fluorescence intensity of daunorubicin (DNR) were determined. In 62 cases of AML, the positive coincidence rate was 73% with MTT test and the negative coincidence rate was 70%. In 3 commonly used drugs, if one drug showed sensitivity, the coincidence remission rate reached 71%. In 51 cases of AML, there were 31 patients in the group of complete remission (CR), in which CFU-L of 29 patients showed independent growth. CFU-L of 2 patients showed no growth. However, there were 20 patients in the group of non-remission (NR), in which CFU-L of 14 patients showed independent growth. CFU-L of 6 patients showed non-growth pattern. Statistical analysis showed significant difference (P < 0.05). In 32 cases of AML, the expression rate of Bcl-2 was 59.55% +/- 19.56% in drug-sensitive group, and one was 77.36% +/- 11.91% in drug-resistant group, respectively (P < 0.05). At the same time, the ratio of Bcl-2/Bax was 7.50 +/- 5.04 in drug-sensitive group and one was 14.32 +/- 8.99 in drug-resistant group, respectively (P < 0.05). In 15 case of clinically drug-resistant AML, the fluorescence histogram of DNR showed left-shift of main peak (LSMP) in 12 patients. They were diagnosed as classical drug resistance. Meanwhile, 1 patient showed right-shift of main peak (RSMP) in 3 patients. They were diagnosed as re-growth drug resistance. It is concluded that MTT and CFU-L might be used for prediction of drug sensitivity or resistance when patients were on treatment. Bcl-2 and ratio of Bcl-2/Bax might be associated with the prognosis. DNR histogram could be employed for identify the pattern drug resistance. The strength and weakness of these techniques were discussed.