To investigate whether the Bcl- 2 gene family is involved in m odulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL - 6 0 cell line and primary acute m yelogenous leukem ic cells,the Bcl- 2 family member Mcl- 1,Bax and Bak and cell cycle proteins including P2 7kipl,P2 1wafl,cyclin D3and p Rbp- were selected and their ex- pression detected by SABC imm uno- histochem ical stain m ethod.The attitude of sub- G1 peak in DNA histogram was determined by FCM.The TU NEL positive cell percentage was identified by term inal deoxynucleotidyl transferase (Td T ) - m ediated Biotin d U NP end labeling technique.It was found that when HL - 6 0 cells were treated with 2 5μm ol/ L curcumin for 2 4 h,the expression level of Mcl- 1was down- regulated,but that of Bax and Bak up- regulated time- dependently.There was significant difference in the expression level of Mcl- 1,Bax and Bak between the curcumin- treated groups and control group(P<0 .0 5 - 0 .0 1) .At the sam e time,curcumin had no effect on progress of cell cycle in prim aty acute m yelogenous leukemia at newly diagnosis,but could in- crease the peak of Sub- G1 (P<0 .0 5 ) ,and down- regulate the expression of Mcl- 1and up- regulate the expression of Bax and Bak with the difference being statistically significant.The expression of P2 7kipl,P2 1wafl and p Rbp- were elevated and thatof cyclin D3decreased in the presence of curcum in. These findings suggested thatthe Bcl- 2 gene fam ily indeed participated in the regulatory process of apoptosis induced by curcumin in HL - 6 0 cells and AML cells.Curcumin can induce apoptosis of primary acute myelogenous leukemic cells and disturb cell cycle progression of HL - 6 0 cells.The m echanism appeared to be m ediated by perturbing G0 / G1 phases checkpoints which associated with up- regulation of P2 7kipl,P2 1wafl and p Rbp- expression,and down- regulation of cyclin D3. To investigate whether the Bcl-2 gene family is involved in modulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL-60 cell line and primary acute m yelogenous leukemia cell, the Bcl-2 family member Mcl-1, Bax and Bak and cell cycle proteins including P2 7 kipl, P2 1 wafl, cyclin D3 and p Rbp-were selected and their ex pression by SABC imm uno- histochem ical stain m ethod. attitude of sub- G1 peak in DNA histogram was determined by FCM. The TU NEL positive cell percentage was identified by term inal deoxynucleotidyl transferase (Td T) - m ediated Biotin d U NP end labeling technique. 5 μm ol / L curcumin for 2 4 h, the expression level of Mcl-1 was down-regulated, but that of Bax and Bak up- regulated time-dependently. There was a significant difference in the expression level of Mcl-1, Bax and Bak between the curcumin- treated groups and control g roup (P <0 .0 5 - 0 .0 1) .At the sam e time, curcumin had no effect on progress of cell cycle in prim aty acute m yelogenous leukemia at newly diagnosis, but could in- crease the peak of Sub - G1 (P <0.05), and down-regulate the expression of Mcl-1 and up-regulate the expression of Bax and Bak with the difference were significantly significant. The expression of P2 7kip1, P2 1wafl and p Rbp- were elevated and that of cyclin D3decreased in the presence of curcum in. These findings suggested that the Bcl-2 gene fam ily indeed participated in the regulatory process of apoptosis induced by curcumin in HL-60 cells and AML cells. Curcumin can induce apoptosis of primary acute myelogenous leukemic cells and disturb cell cycle progression of HL - 60 cells. The m echanism was to be mEdiated by perturbing G0 / G1 phases checkpoints which associated with up-regulation of P2 7 kip1, P2 1 wafl and p Rbp-expression, and down - regulation of cyclin D3.