3981
In preliminary studies, we have analyzed the hematopoietic growth factor ( HGF ) requirement of hematopoietic progenitor cells ( HPCs ) purified from embryonic-fetal liver ( FL ) and grown in fetal calf serum-supplemented (FCS+) clonogenic culture .
 ( cell type: HPCs, None) , ( cell type: hematopoietic progenitor cells, None) , ( protein: HGF, None) , ( protein: hematopoietic growth factor, 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: HPCs, None) , ( cell type: hematopoietic progenitor cells, None) , ( protein: HGF, None) , ( protein: hematopoietic growth factor, None) 