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In sum , these results demonstrate that conjugation of chitosan - PEG - FA to oncolytic Ad significantly improves antitumor efficacy and safety profiles , suggesting that Ad / chitosan - PEG - FA has potential as a therapeutic agent to target FR - positive cancer via systemic administration .
 PEG - FA, PEG - FA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 PEG - FA, PEG - FA