Abstract: ObjectiveTo study the effect of β-carotene and vitamin C on the expression of c-myc oncogene in human leukemic cell.MethodsLeukemic cell K562 was cultured in vitro for 24h,48h,72h by adding different concentration of βcarotene and vitamin.Meanwhile,trypan blue exclusion method and DNA gel electrophoresis and Northern blotting hybridization were used to detect the cell proliferation,the apoptosis and the expression of the c-myc gene.ResultsThe proliferation of non-myelogenous leukemic cell line K562 was inhibited after exposed to Vit C(5、10、100μmol/L)and the effect occurred earlier at low concentration(5μmol/L)or high concentration(100μmol/L).β-carotene at concentrations(10-100μmol/L) could inhibit the proliferation of non-myelogenous leukemic cell line K562.The apoptosis of K562 cell were induced by Vit C(5μmol/L)and β-carotene(50μmol/L).Vit C(5μmol/L)could not influence the expression of c-myc gene(P>0.05), but β-carotene could up-regulating the expression of c-myc(P<0.05).ConclusionThe inhibitory effect of β-carotene on the proliferation of leukemic cell was caused by the induction of apoptosis of K562 through up-regulating expression of c-myc gene,though the inhibitory effect of vitamin C on the proliferation of the cell was not related with expression of cmyc gene.