6718
Our data demonstrate that those cell lines lacking capability to form metastatic tumors in vivo are susceptible to TNF induced apoptosis in vitro.
 ( cell line: cell lines, None) , ( protein: TNF, 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 line: cell lines, None) , ( protein: TNF, None) 