13943
Additional experiments showed that levels of BCL-2 protein decreased during differentiation of myeloid leukemic cells .
 ( cell type: myeloid leukemic cells, None) , ( protein: BCL-2 protein, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( cell type: myeloid leukemic cells, None) , ( protein: BCL-2 protein, None) 