OBJECTIVE: To investigate the effects of quercetin on cell morphology and VEGF 
expression of acute myeloblastic leukemia cells NB4 in vitro.
METHODS: The cytomorphology of NB4 cells was assessed by Wright-stain, apoptosis 
rate by apoptotic marker Annexin V, and VEGF secretion level by ELISA.
RESULTS: Typical apoptosis was found in NB4 cells after treatment with 
quercetin. Apoptotic marker Annexin V analysis showed that the apoptotic rate of 
NB4 cells was increased after treatment with quercetin. The secretion of VEGF of 
NB4 cells was significantly decreased after treatment with quercetin.
CONCLUSION: Quercetin can induce apoptosis and inhibit secretion of VEGF in NB4 
leukemia cells.