4002
Using a competitive inhibition strategy , we used phage display techniques to identify 53 single - chain variable fragments ( scFvs ) after three rounds of panning against FAP .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None