7579
In this study we explored the effects of retinoic acid ( RA ) on apoptosis of human CD34+ hematopoietic progenitor cells isolated from normal bone marrow.
 ( cell type: human CD34+ hematopoietic progenitor cells, None) , ( cell type: hematopoietic progenitor cells, 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: human CD34+ hematopoietic progenitor cells, None) , ( cell type: hematopoietic progenitor cells, None) 