In vivo effect of Catechins on murine models of APL. (A) Catechins decreased the tumor volumes in a murine xenograft model. Nude mice were received 3 Gy radiation one day before subcutaneous injection with NB4 cells. The treatments began 10 days later including control diluent (n = 5) and Catechins (10 mM) (n = 5) daily for 21 days. The tumor volumes of control mice and Catechins-treated mice on Day 31 were measured. Catechins significantly reduced the xenograft tumor volumes (*P < 0.05). (B) Apoptotic cells detected by TdT-FragEL™ DNA Fragmentation Detection kit were calculated. A significantly increased number of apoptotic cells was observed in the Catechins group, comparing with the untreated group ***P<0.001.