7703
Brief exposure to fludarabine led to a sustained loss of STAT1 , analogous to the prolonged period of immunosuppression induced by exposure to the drug in vivo.
 STAT1
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 STAT1