RESUMO
<p><b>OBJECTIVE</b>To preliminarily identify the existence of CD34leukemia stem cell (LSC) in t(8;21) acute myeloid leukemia (AML) by in vitro test.</p><p><b>METHODS</b>Bone marrow samples collected from newly diagnosed t(8;21) AML patients were tested. LinCD34CD38(abbreviation, CD34CD38), LinCD34CD38(abbreviation, CD34CD38) and LinCD34CD38CD45SSC(abbreviation, CD34"LSC") cell fractions were gated by flow cytometry after staining with fluorescent antibodies. Cells in Gphase were identified through Hoechst 33342 and pyronin Y staining. Aldefluor reagent was used to test aldehyde dehydrogenase (ALDH) activity. The above-mentioned 3 cell fractions were sorted, and mRNA levels of AML1-ETO and WT1 were measured by real-time quantitative PCR.</p><p><b>RESULTS</b>The 3 tested samples displayed the same tendency in ratio of the cells in Gphase: CD34"LSC">CD34CD38>CD34CD38. The paired t-test of 53 patients showed that frequency of ALDHcells of both CD34CD38and CD34"LSC" cell fractions was significantly higher than that of CD34CD38(P<0.01), furthermore, the ALDHcell frequency was significantly higher in CD34"LSC" than that in CD34CD38(P<0.01). AML1-ETO mRNA levels of cells sorted from 3 patients were similar among the 3 cell fractions within each patient, whereas WT1 mRNA levels were significantly higher in CD34"LSC" than that in other 2 cell fractions.</p><p><b>CONCLUSION</b>CD34LSC may exist in t(8;21) AML, and may be more primitive than CD34LSC. These results promote the necessity to perform in vivo xenogeneic transplantation mice.</p>