3229
Cells with nuclear p50 were negative for the CD38 , CD20 and CD2 markers .
 ( protein: CD38, None) , ( protein: CD2 markers, None) , ( protein: CD20, None) , ( protein: p50, 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: CD38, None) , ( protein: CD2 markers, None) , ( protein: CD20, None) , ( protein: p50, None) 