5726
Loss of both cytolytic susceptibility and sensitization to chemically induced apoptosis was coselected during in vivo selection of E1A -positive sarcoma cells for increased tumorigenicity .
 ( cell type: E1A -positive sarcoma cells, None) , ( protein: E1A, 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: E1A -positive sarcoma cells, None) , ( protein: E1A, None) 