7258
In a model where foreign cells ( rat fibroblasts ) were cocultured with human IL-2 activated NK cells , we observed that NK cells were capable of efficiently killing their targets only if the cells overexpressed the oncogene c-Myc or E1A .
 ( cell type: NK cells, None) , ( protein: E1A, None) , ( cell type: NK cells, None) , ( cell type: foreign cells, None) , ( protein: c-Myc, None) , ( cell type: human IL-2 activated NK cells, None) , ( protein: IL-2, None) , ( cell type: rat fibroblasts, 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: NK cells, None) , ( protein: E1A, None) , ( cell type: NK cells, None) , ( cell type: foreign cells, None) , ( protein: c-Myc, None) , ( cell type: human IL-2 activated NK cells, None) , ( protein: IL-2, None) , ( cell type: rat fibroblasts, None) 