9038
All the tumors exhibited very low proliferative activity, fewer than 10% of the tumor cell nuclei being stained by the antibody MIB-1 ( Ki-67 antigen ).
 ( protein: Ki-67 antigen, None) , ( protein: antibody MIB-1, None) , ( protein: Ki-67, 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:
 ( protein: Ki-67 antigen, None) , ( protein: antibody MIB-1, None) , ( protein: Ki-67, None) 